Haswett—A Monograph of the Temnocephalee. 145 
other hand, are in all essential respects similar to those of Zyzstomume mole. The 
tactile cones, so abundantly distributed on the tentacles and anterior part of the body 
in Temnocephala and Craspedella, and on the posterior fringes and processes of the 
latter genus, seem to have been found elsewhere in a similar shape only in 
Sphyranura; but the motionless hairs of many Rhabdocela are evidently structures 
of the same fundamental character. 
As regards the reproductive organs—it appears to me that Zemmnocephala finds 
closer alliances among the Rhabdocceles than among the ectoparasitic Trematodes ; 
and of the former group various Vortic7d@, as described by von Graff and others, 
approach very near to it in the general arrangement of parts, as well as in the special 
character of the cirrus. A bursa copulatrix is absent in both Zemnocephala and 
Craspedella, but the muscular “vagina” of 7. Nove-zealandie, though leading directly 
to the uterus and oviduct, may represent it, and the teeth in its interior, though more 
numerous, bear a striking resemblance to those of the bursa copulatrix of some of the 
Rhabdoceeles, such as Proxenetes flabellifer, Jensen (von Graft, Taf. vin. fig. 16). 
But spines or teeth occur round the opening of the oviduct in Ax7xe and Microcotyle. 
The testes resemble the compact type of these glands occurring among the 
Rhabdocela,; but are also nearly approached by those of some ectoparasitic Trematodes. 
The ovary has in many Rhabdocceles the same form and relations as in 7enznocephala; 
but in the form and arrangement of the ova within the ovary there is a much nearer 
resemblance to Sphyranura of the Monogenea. 
A remarkable point of resemblance between 7emxocephala and the Rhabdocela is 
in the system of accessory glands secreting rounded granules connected with the male 
reproductive apparatus in both groups. Von Graff's account of these structures as 
they occur in the Rhabdocceles applies equally well, word for word, to Temnocephala 
—the only difference of consequence being in the much greater length of the ducts in 
the latter case. The so-called prostate-glands of some Wonogenetica are evidently 
the same structures less specially developed. 
Stalked eggs similar to those of Temnocephala occur among the Rhabdocceles— 
the “stalk” in the latter, as in some of the species of Zemmnocephala, not always 
serving for the attachment of the ege. But similar eggs are met with also among 
the monogenetic Trematodes. Sufficient data are wanting for a comparison of the 
embryological history in the various groups under discussion. What is known does 
not seem to tell more in one direction than in another. The embryo of Temnocephala 
undergoes direct development and becomes fully formed while still within the egg— 
the reproductive apparatus alone remaining undeveloped. This direct development 
and absence of metamorphosis it shares equally with the monogenetic Trematodes 
and with the Rhabdocela. 
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