ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 889 



as iu tlicir natural haunts; his careful observations of dates and 

 measuremeuts are, however, of considerable importance. He observed 

 a mure rapid change from the larval to the true Brachyuran form 

 than that gradual alteration described by Spence Bate in his classical 

 paper on the Development of Decapod Crustacea. 



' Challenger ' Isopoda.* — F. E. Beddard gives a preliminary 

 notice of some of the Jsopoda collected during the voyage of H.M.S. 

 ' Challenger.' Sixteen sjiecies of Serolis were dredged, nine being new 

 species. Four are deep-water forms, the remaining new species having 

 been dredged iu shallow water off the coasts of S. and E. Australia. 

 The geographical distribution of Serolis is " limited and peculiar," 

 being almost entirely confined to the Antarctic hemisphere. The 

 deep-sea forms have a wider range than the shallow-water species, 

 although none have as yet been found north of the equator. 



The differences noted between deep- and shallow-water forms 

 occur (1) in the epimera (especially the 6th pair) which are much more 

 elongated in the deep-water forms than in other, and (2) in the eyes. 



In deep-sea forms of Serolis Mr. Beddard found that no veritable 

 retinula was ever developed. A vitreous body is represented, and the 

 cornea may, or may not, be facetted. In shallow-water forms, on the 

 other hand, the eyes are invariably well developed, and resemble those 

 of other Isopoda. These facts are interesting as bearing on the theory 

 of " abyssal light," the presence of eyes in the deep-sea forms (one of 

 which was dredged from 2040 fathoms) serving to enable these 

 animals to perceive the light emanating from phosphorescent Alcyo- 

 narians. Fuller details will appear in the forthcoming ' Challenger ' 

 Memoir on the Isopoda, now in the press. 



The Cryptoniscidae.t— R. Kossmann first directs himself to the 

 question of the relation of the sexes in these parasitic Isopoda and 

 comes to the conclusion that the mature males retain their larval form 

 and have swimming feet on the jjleon ; the f male, however, is not 

 fertilized until it has passed through a metamorphosis, and become fixed 

 and greatly degenerated. This is not, at the same time, the whole 

 of the story : Kossmann is convinced that both forms are only the 

 developmental stages of one and the same individual : in other words, 

 the Cryptoniscidae exhibit protandric hermaphroditism ; and so far 

 remind us of what obtains in the allied Cymothoidse. 



The chief pai"t of what remains of the digestive apparatus after 

 degeneration appears to be the homologue of the so-called liver of the 

 rest of the Crustacea ; but it has not a hepatic function, its lumen 

 receives the food of the parasite, which is identical with the blood of 

 the animal on which it is parasitic; the food is here digested and 

 absorbed. The " liver " of other Crustacea is likewise not a hepatic 

 organ, the name was erroneously given to it on account of its colora- 

 tion. Hoppe-Seyler and Krukenberg have discovered in it ferments 

 which have a diastatic, a peptic, a tryptic, and a fat-reducing property, 

 and M. Weber has applied to the organ the name of hepato-paucreas ; 



* Proc. Zool. Sue. Loud., 1884, pp 330-41. 

 t SB. K. PreusB. Akad. Wise., 1884, pp. 456-73. 

 8er. 2.— Vol. IV. 3 n 



