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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Hymenolepis carioca | definition of Hymenolepis carioca by Medical dictionary

Excretory system in scolex. The foregoing facts, I believe, furnish a very good demonstration of the untenability of Cohn’s division of the genus. There is a basket-like plexus of small canals figs. 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.

Fibers which cross at right angles between the two strands of the commissure establish a continuity between these dorsal and ventral nerves. In the scolex they attach to the suckers, two to each. The margins of the strobila are serrate fig. The central portions are continuous, while the peripheral portions are separated from one another by the constrictions.

The head measured 0. Specimens in my possession of Hymenolepis sp.


The cirrus pouch fig. Dorsal view of very young segments. Cirrus pouch and seminal receptacle. Apart from this question it is not even certain that he has wisely modified the definition of the genus in restricting the number of testes to three.

Reconstruc- tions from transverse sections through scolex behind the rostellum. Hymenolepis megalops Nitzsch Was first found by Nitzsch in the intestine of Anas boschas and Dafila acuta. While the cerebral commissure connecting the main lateral nerves in T. Frontal section of carioxa.


Ward I am indebted to Dr. The cirrus pouch cp cariocca, seminal vesicle vsand seminal receptacle sr are usually easily recognizable in uymenolepis specimens. The recurrent limb of the ventral loop turns outward like the corresponding limb of the dorsal vessel, passes behind the latter, and extends between the suckers toward the lateral surface carioxa the scolex, finally turning anteriad to run forward in the same frontal plane as the dorsal vessel, between it and the surface of the head figs.

Transverse section through the posterior region of one of the first 35 segments. The ventral root is long, while the dorsal root is only a mere knob. Both forms possess unilateral genital pores, reproductive canals dorsal to the nerve and excretory canals, three testes, a large carikca vesicula outside the cirrus pouch, and a sec- ond smaller one within. There is, however, a well-defined bilobed ganglionic mass fig.

The lateral longitudinal nerves In arise from the postero-lateral corners of the ganglia figs. The bundles of this layer are of about the same size throughout the strobila, and hence in the posterior segments fig.

There are accordingly two closed loops of the excre- tory system extending forward into the rostellum, as in Hymeno- lepis carioca and H. A transverse canal connects the ventral canals in the posterior part cadioca each seg- ment. With regard to its reproductive organs as well as in other respects Hymenolepis carioca is quite comparable to H.


This muscle layer, which is very heavy and prominent in the anterior segments fig. Through the kindness of Dr. The length of one of the small specimens was 4 mm. Transverse fibers are not present except a few in the pos- terior region fig. I am able to confirm Grassi’s observations, in part, as I have sections hhymenolepis H. Surrounding each sucker near its posterior pole is a circular ring or zone of nerve fibers, lying in the same horizontal plane as the transverse cerebral commissure, and joined to it at its point of union with the lateral nerve.


Inner envelope Onchosphere Hooks 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. Moreover, such genera as Monopylidium and Cotugnia, although their suckers are unarmed, resemble Davainea cariocca much to be placed in a separate subfamily, and certainly have more in common with J 54 B.

As the uterus enlarges the ovary quickly disappears, and the former soon comes to occupy all the available space within the proglottis fig. The yolk gland yg is spherical or ovoid, 30 p. In the scolex the canals of both sides turn inward and approach each other as they pass forward.

This bulb is apparently homologous to the vaginal sphincter of Drepanidotaenia lanceolata described by Wolff hiigel 00a.