394 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cells in the anterior region of the germ ; its wall gives rise to two for- 

 w^arclly directed outgrowths which flatten out and grow np on either side ; 

 these lateral walls rapidly fuse in the anterior region ; before they do so, 

 however, they give rise to two hepatic saccules. The hinder part of the 

 gut partly closes up, but the median jjortion still remains open, and in 

 contact with the nutrient yolk. The anterior side of the liindgut now 

 lies very close to the midgut. The author was Tinable to find any of the 

 so-called yolk-cells ; the cells of the primary endoderm do not lie within 

 but between the yolk-spherules, and the remarkable absorption of the yolk 

 is only effected by the differentiating cells of the endoderm, which form the 

 midgut and liver-saccules. 



In Porccllio as in Oniscus (described by Kusbatim) the second pair of 

 hepatic outgrowths is formed by longitudinal division of the outgrowths of 

 the first pair. 



Capon.* — MM. A. Giard and J. Bonnier discuss the characters of the 

 genus Ce2)on, a Bopyrid from Mauritius, which was discovered in 1840, but 

 whose host was unknown ; in 1881 it was found at Naples in Porluniis 

 arcuatus. Two new species have lately been discovered at Concarneau in 

 Xantho floridus [Cepon pilula), and at Wimereux, where C. elegansis not very 

 rare in Pilumnus liirtellus ; the parasite is found in the upper part of the 

 branchial cavity, and generally its hosts are young examples. The forms 

 figured by Duvernoy as males are really young females not entirely trans- 

 formed ; the species found on Cancridae hold to the Cepon of the Portunidfe 

 the same relation as in Entione is held by Cancrlon to Portunion ; they are 

 less profoundly modified just as are their hosts. The embryo of C. elegans 

 has a considerable resemblance to that of Phrijnus paguri ; in both a young 

 male and in Entione a Crypioni sens-stage has been observed to succeed the 

 first larval form, and as this has been found in Pi>p>yrina virhii and in 

 Phrynus this second larval stage may be supposed to be common to all the 

 Bopyridfe ; it is in this stage that they probably make their way into their 

 hosts. 



'Challenger' Isopoda.f— Mr. F. E. Beddard, who has already pub- 

 lished a preliminary report on the ' Challenger ' Isopoda here collects and 

 illustrates his accounts. It is proposed to form a new genus, lanthopsis, for 

 lantlie hovalli ; and a few sj^ecies are here described for the first time. Deep- 

 sea Isopoda appear to be distributed very unevenly over tlie floor of the 

 ocean, long stretches being altogether devoid of them. Thirty-four of the 

 deep-sea species are blind, while in eighteen there are well-developed eyes ; 

 but of the eleven specially deei)-sea genera representatives of two alone liad 

 eyes ; the reason for some sijecies retaining their eyes while others lose them 

 on migration into deeji water is j^erhaps to be sought for in the difference of 

 the length of time that the respective species have inhabited great depths. 

 Among Isopods the deep-sea fauua comprises many species which are larger 

 than their shallow-water representatives, the colossal Batliynomus giganteus, 

 described by Prof. Milne-Edwards, measuring nine inches in length. 

 Deep-sea sjiecies often exhibit a great develojiment of spines on the body ; 

 this is most noticeable among the Arcturi, but it is perhaps a character 

 dependant rather on temperature than depth, for it has been observed in the 

 species which iidiabit cold regions. 



Anatomy of Internal Male Organs of, and Spermatogenesis in 

 Cypridse-I — Di"- F. Stuhlmann finds that the four testicular tubes of either 



* Comptcs Reudus, ciii. (1880) pp. 889-92. 



t Reports of the Voyage of H.M.S. •Challenger,' Monograph xlviii. (1887) 178 pp., 

 25 pis. X Zcitschr. f. \Vi.ss. Zool., xliv. (188G) pp. 53G-G9 (I pi.). 



