786 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of a thin structureless membrane, bounded internally by a single layer 

 of cells ; the penis has a very thick cuticle, and in Solenophorus is of 

 some considerable length. 



Studies on Cestodes.* — E. Moniez here treats chiefly of species of 

 Tcenia. In T. pectinata the uterus becomes modified very considerably 

 in the older segments ; its caeca become covered with a thick layer of 

 granules which appear to result from luxuriant cellular proliferation 

 of its walls. The granules become detached, and fall into the cavity 

 of the uterus ; some of them invest the embryos as a cuticular invest- 

 ment, and the rest form a reticulum which encloses the latter; a 

 similar process takes place in T. cucumerina. The vessels in T. pecti- 

 nata form numerous large anastomoses between each other. In 

 another species, resembling T. expansa, T. cucumerina, &c, a possibly 

 glandular mass is situated upon the oviduct, with cells each exhibiting 

 an immense vacuole. The uterus forms two tubes extending from 

 side to side of the segment, viz. on the ventral and dorsal surfaces, and 

 lying on the muscular layer. When the uterus is full of ova, wide 

 communications are seen between these main divisions. In T. giardii, 

 the male organs are placed at the two ends of the segment ; the 

 spermatozoa of one side cross the segment and issue by the opposite 

 vas deferens, the two currents crossing on the dorsal side. In young 

 segments the vagina is very large, and the ovary appears by contrast 

 to be merely an appendage of it, but later it envelopes and conceals it. 

 The ovum does not exhibit the vitelline masses which appear towards 

 the end of development in T. expansa. Besides the normal muscles 

 are found some large fusiform cells, quite distinct from them, 

 especially abundant in the central zone ; in the old segments they 

 are strongly refractive, and devoid of granules ; they appear to be 

 homologous with the mother-cells of the calcareous corpuscles. No 

 • vitellogenous glands exist in any of the species referred to. 



Ligula and Schistocephalus.t — Herr F. Kiessling, working in 

 the laboratory of Professor E. Leuckart, has detailed the structure of 

 Schistocephalus dimorphus and Ligula simplicissima. He maintains 

 the generic distinction of these tape-worms in opposition to Donnadieu, 

 whose description of Ligula (published in Eobin's Journal for 1877) 

 he corrects in several particulars. As containing a revised account 

 of two rather aberrant cestoids, presenting many noteworthy points of 

 agreement, this essay has a value of its own ; in so far as it deals with 

 anatomical questions concerning tape-worms generally, it supports 

 the views set forth by Herr Kiessling's teacher in the current edition 

 of his great work. 



These cestoids, when mature, inhabit the gut of water-birds. 

 While L. simplicissima, in its asexual phase, infests malacopterous 

 fishes, the larval Schistocephalus is a parasite of the body-cavity of 

 the common stickleback. Both larvte agree in being injurious to their 

 hosts, so that external inspection reveals their presence. Curiously 

 enough, Schistocephalus could not be found throughout a wide area 



* Comptes Rendus, xciv. (1882) pp. 661-3. 



t Arch. f. Naturgesch., xlviii. (1882) pp. 241-80 (2 pis.). 



