Malalmaran That this difference is not so important as may seem is shown by the fact that the number of testes in humenolepis of H. 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 carioxa to that genus. The posterior margins are not prolonged back- ward to any extent, so that there is little or no overlapping of the segments. The median and accessory lateral nerves are con- nected behind the complex by numerous commissures with one an- other and with the main lateral nerves. With progressing de- velopment a cavity is formed by a hollowing out of the cord, and humenolepis uterus becomes a thin-walled sac which grows backward on the dorsal side of the ovary. The lateral nerves are joined in three regions fig.
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Groran Diesing 50, 64 merely adds to the list of hosts. In connection with each commissural ring of the pro- glottis in T. A number of nerves extend forward from the same points.
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 dorsal and ventral median nerves join the complex fig. MEGALOPS 1 59 hand, that the external characters are peculiar enough to enable one to identify it easily, and with little or no chance of error. They are very thin and close together, and run around the vagina in a circular direction, so that in a longitudinal section they appear as a thick coat of cilia.
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. In two specimens examined the dorsal limb of the right-hand loop came from the ventral vessel, of the left-hand loop from the dorsal vessel fig. Scarcely larger than a coarse thread at its posterior end, it tapers gradually anteriad, becoming exceedingly tenuous at the neck.
JSTOR is a digital library of academic journals, books, and primary source objects. The median and accessory lateral nerves are con- nected behind the complex by numerous commissures with one an- other and with the main lateral nerves. 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. Frontal section through a mature segment No.
The central portions are continuous, while the peripheral portions are separated from one another by the hymenolelis. Two figures by Creplin 29 are reproduced by Braun The yolk gland yg is spherical or ovoid, 30 p.
The suckers are spherical, 0. Since the segments do not tend to break off singly 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.
In segment it is represented by a little lenticular mass of cells 50 p. The opening of the vagina into the cloaca is carkoca and posterior with respect to the cirrus. Hymenolepis carioca definition of Hymenolepis carioca by Medical dictionary According to this view Taenia spiculigera?
Consequent hymeno,epis the separation of a ripe segment from the strobila, however brought about, a large area of the surface of the uterus is laid bare, and in this area a thin membrane is all that sep- arates the embryos from the outer world, facts which may play a part in their dispersal. There is a basket-like hjmenolepis of small canals figs. Specimens in my possession of Hymenolepis sp. The sac-like rostellum fig. It is almost cylindrical, rarely perfectly straight, but bent more or less, usually toward the ventral surface in a gentle curve fig.
The arrangement of the organs within the cirrus pouch is similar to that of Drepanidotaenia lanceolata Wolff hiigel 00a. The two halves of the commissure are connected by fibers running diag- onally from one to the catioca, and between them lie numerous ganglion cells. Inward it may extend consider- ably beyond the proximal end of the cirrus sac. It has, however, a seminal vesicle outside the cirrus pouch, besides the one within described by Jacobi. Before entering the cirrus pouch it passes beyond the base of the latter and then folds back to form a small loop in which are commonly found one or two vesicular enlargements fig.
The subfamily Davaeneinae consequently can no longer be maintained upon its original basis. The loops lie in nearly the same transverse plane. 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 slender, pointed blade forms an angle of 90 to with the ventral root. The form described by Jacobi 98 as Taenia inflata Rud. The other two were larger, and considerably more advanced in development, as several of the posterior segments con- tained embryos which were yet, however, without hooks.
It is therefore questionable whether such a difference is sufficient to separate generically two forms otherwise similar, whose lack of agreement in this regard may be explained as the result of a slight variation, which, although oc- curring but occasionally in one, has become permanent and normal in the other.
Beitrag zur Kenntnis der Vogelhelminthen. Although the opening of the vagina fig. This cerebral complex corresponds roughly to that of Taenia crassicollis as given by Cohn My observations agree less closely with those of Tower The blade of the largest hooks measures 6 ft to 7.
Transverse fibers are not present except a few in the pos- terior region fig. Cirrus pouch and seminal receptacle. The number of segments was Between the first and second turns of the vas deferens, dorsal to the cirrus pouch, there is an enlargement, the vesicula seminalis figs. A line drawn transversely through the very base caripca one segment will pass through the margin of the preceding segment very near its genital pore.
The form possesses hykenolepis testes and in the details of cirrus pouch, the two seminal vesicles, seminal receptacle, ovary, yolk gland, and anlage of uterus shows striking similarities to H.
The under surface of the rims is marked by tiny longitudinal ridges in the cuticula, folds made necessary by the decrease in area of the under surface when the rims, instead of extending carloca as in the youngest segments, come to point backward, as they do more and. Related Posts
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