PRELIMINARY NOTE ON THE LIFE HISTORY OF HYMENOLEPIS CARIOCA. By Myrna F. Jones. See allHide authors and affiliations. Science 23 Nov Hymenolepis may refer to: Hymenolepis (plant) · Hymenolepis (tapeworm) · Disambiguation icon. Disambiguation page providing links to articles with similar . 1. Science. Nov 23;68() PRELIMINARY NOTE ON THE LIFE HISTORY OF HYMENOLEPIS CARIOCA. Jones MF. PMID:
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Through the kindness of Dr. Conard I have had the privilege of seeing his manuscript, as well as his material and preparations, which have proved of great assist- ance in the identification of my specimens. The worm in question is very slender and delicate. Scarcely larger than a coarse thread at its posterior end, it tapers gradually anteriad, becoming exceedingly tenuous at the neck.
The length ranges from 30 mm. The margins of the strobila are serrate fig. The posterior margins are not prolonged back- ward to any extent, so that there is little or no overlapping of carioac segments. Throughout the strobila the width of the segments is three to five times, or more, greater than their length ; the worm is thus of the type cariocaa short segments such as Hymenolepis diminuta and others of the genus.
It measures as it B. The rostellum is un- armed.
Hymenoleps head, sectioned in situ with a hy,enolepis of intestine, pos- sessed, upon the suckers, hooks fig. The ventral root is long, while the dorsal root is only a mere knob. The slender, pointed blade forms an angle of 90 to with the ventral root. They are of the same type as the hooks from the suckers of Davainea Friedbergeri Stiles 96, fig. The blade of the largest hooks measures 6 ft to 7. The round neck measures from 0.
The genital pores are situated upon the right-hand margin of the strobila, normally somewhat in front of the middle of each seg- ment fig. Very rarely a pore will be found on the left-hand margin. The cirrus pouch cpseminal vesicle vsand seminal receptacle sr are usually easily recognizable in toto specimens.
In ripe segments the last fig. The last 30 to segments are crowded with embryos so that the median field of each is fully oc- cupied fig. Since the segments do not tend to break off carioxa from the strobila as they become ripe, and since the embryos which they contain form practically a continuous mass extending unbroken from one proglottis to the next, if a portion of the worm be broken off from its posterior end the entire series of proglottides will con- stitute what is in effect but a single embryo sac.
Four membranes may be distinguished surrounding the oncho- sphere fig. The space between the middle two is filled with a granular mass, and potentially, as well as actually in some cases, these two membranes, by close approximation, constitute but a single envelope. The three outer layers are thin and colorless, while the innermost next the embryo is often slightly tinged with yellow and is usually thicker than the others.
Inner envelope Onchosphere Hooks fig. The presence of hooks upon the suckers might ap- pear as a confirmation of the supposition made by Magalhaes that the species is a Davainea, but beyond this characteristic it possesses none of the peculiarities of that genus.
The fact alone that it has a definite and persistent uterus precludes the possibility of such a generic relationship, and furthermore its close structural resem- blances to the type of Hymenolepis justify its immediate reference to that genus. The possession of armed suckers by a species of Hymenolepis is significant in that it demonstrates how little importance can be attached to such a character in establishing generic relationships. In fact, in many cases it can not be hymenolepsi of more than specific cqrioca.
He has thus bound together three groups of forms resembling each other only in the possession of armed suckers, and at the same time has sep- arated the group Davainea from other forms which bear close re- semblances to it in many respects, but do not have hooks hyenolepis the suckers. Beyond the fact that Echinocotyle and Ophryocotyle have armed suckers there can be no excuse, so far as our knowledge of their anatomy goes at present, for grouping them with Davainea.
Moreover, such genera as Monopylidium and Cotugnia, although their suckers are unarmed, resemble Davainea too much to be placed in a separate subfamily, and certainly have more in common with J 54 B. The subfamily Davaeneinae consequently can no longer be maintained upon its original basis.
There is, however, a well-defined bilobed ganglionic mass fig. From it nervous processes an pass anteriad along the sides of the rostellum, within which, also, there is a considerable amount of nervous tissue. The lateral longitudinal nerves In arise from the postero-lateral corners of the ganglia figs. The accessory lateral nerves are very small and only occasionally uymenolepis in the segments, lying a short distance dorsal and ventral from the main nerves.
In the scolex they attach to the suckers, two to each. These slender strings comprise the inner longitudinal muscle layer, cariocaa correspond to the eight inner longitudinal muscle bundles of Taenia inflata Rud.
[1st proof of Hymenolepis carioca in Lower Austria].
The outer layer of longitudinal muscles om consists of about hymenoleois hundred muscle strands similar to the inner muscles and like them continuous hykenolepis segment to segment.
The origin of these muscles is similar to that of the outer longitudinal muscles of Anoplo- cephala perfoliata as described by Liihe hymenloepis, 96i. A layer of diagonal muscles fig. A transverse muscle system is represented only by a few slender iso- lated fibers tmrestricted mostly to the extreme anterior and posterior ends of hymdnolepis segment, as is the case in many other forms of the genus. A few dorso-ventral fibers are also found in these regions. The sac-like rostellum fig.
Near the middle of the rostellum the dorsal vessel varioca each side unites with the ventral vessel so that two closed loops are formed. Branches of the excretory system apparently sim- ilar to these loops have been described by Mingazzini 99 for Hymenolepis murina.
I have also found exactly similar loops in the rostellum of H. The ventral excretory vessels are larger than the dorsal vessels from the beginning fig. In the scolex the former measure 6 ft, the latter 4 p.
Transverse vessels connect the ventral vessels at irregular intervals of two to seven segments, usually at an interval of about five. The vasa efferentia fig. It here turns to the left, then curves ventrad, and finally, bending to the right, enters the base of the latter. Between the first and second turns of the vas deferens, dorsal to the cirrus pouch, there is an enlargement, the vesicula seminalis figs.
The body of one of these cells is some 6 p or 8 p. The protoplasm is compact and finely granular, and each cell contains a spherical nucleus 2 p. These hymenolepls are to all appearances exactly similar to the cells found in caeioca same position but in much greater numbers in Taenia transversaria, Taenia expansa, and Calliobothri- um coronatum, described by Zschokke 88 as prostate glands.
I was unable to demonstrate, however, that these cells opened into the cavity of the vas deferens in H. The cirrus pouch fig.
[1st proof of Hymenolepis carioca in Lower Austria].
It is almost cylindrical, rarely perfectly straight, but bent more or less, usually toward the ventral caroica in a gentle curve fig. Similar muscle bands have been described in Taenia depressa by Fuhrmann 95in Taenia iniiata by Jacobi 98in Fimbriaria fasciolaris and Dicranotaenia coronula by Wolffhiigel 00as well as in other forms by different authors. Hymenolepis carioca is remarkable by reason of the small number of these bands, and their relatively large size.
Surrounding the middle part of the cirrus pouch is a layer of carioda figs. These myoblasts are most prominent in the young segments before spermatozoa are found in the vas deferens. Cir- cular muscles are lacking, and the membrane of the cirrus pouch fig. Upon entering the cirrus pouch the vas deferens is much constricted fig.
In thickness and general appearance, the wall of this narrow portion of hymenolspis vas deferens resembles the membrane of the pouch, which seems to have turned in at this point to form a narrow tube through which the vas deferens passes.
Beyond this narrow portion the vas deferens is dilated to form a second seminal vesicle figs. At a point about one-third the length of the pouch from its distal end, the vas deferens becomes narrow again, to form the cirrus fig. Both the cirrus pouch and the vagina are dorsal to the nerve and the ex- cretory canal.
From the diagonal muscles of the proglottis fibers turn in to attach to the outer portion of the cirrus sac, serving thus as protractors fig. The longitudinal fibers come from the diagonal system, or from the subcuticular longitudinal muscles, and attach to the tip of the cirrus pouch to form part of the system of protractors. The opening of the vagina into the cloaca is ventral and posterior hmenolepis respect to the cirrus.
This bulb hymeholepis apparently homologous to the vaginal sphincter of Drepanidotaenia lanceolata described by Wolff hiigel 00a. Be- yond the sphincter the vagina gradually enlarges, and swells out into a seminal receptacle, which may grow to be very large, so as to reach forward to the anterior limits of the cqrioca, and even crowd in cariocx the organs of the next.
Inward it may extend consider- ably beyond the proximal end of the cirrus sac. At its maximum it extends from one excretory canal to the other. The yolk gland yg is spherical or ovoid, 30 p. The uterus at first is simply a solid cord of cells fig. With progressing de- velopment a cavity is formed acrioca a hollowing out of the cord, and the uterus becomes a thin-walled sac which grows backward on the dorsal hymenoolepis of the ovary.
As the uterus enlarges the ovary quickly disappears, and the former soon comes to occupy all the available space within the proglottis fig. The wall of the uterus con- sists of a thin membrane fig. During the growth hyenolepis the uterus a number of infoldings arise in its wall, mostly in the form of tubular processes, a few of which meet and fuse to B.
RANSOM form slender, bridge-like connections, so that finally the uterus is modified to a slight degree from its original simple sac-like condi- czrioca. With regard to its reproductive organs as well as in other respects Hymenolepis carioca is quite comparable to H. Both forms possess unilateral genital pores, reproductive canals dorsal to the nerve and excretory canals, three testes, a large sac-like vesicula outside the cirrus pouch, and a sec- ond smaller one within.
A large seminal receptacle, hymenolepos more or less bilobed ovary, and a yolk gland posterior and dorsal to the latter are also present in both.
The uterus in both arises first as a trans- verse tube anterior to the ovary, later filling the segment, and in each case is not a simple sac, but characterized by a greater or less number of inturned processes hmyenolepis bridges of tissue developed from its walls. Apart from the major complications arising during the growth of the uterus of H.