Gen-: CvrkONiscus, Kossiuann, 



1884. Cyproiiisciis, Kossnianu, Sitzungsbcrichte K- Akad. Wiss- 



iierliu, Heft 22, p. 4O0. 

 1887. CypivnisciiSj Giard and Bonnier, Travaux d(j Wimereux, 



ijopyrieus^ p. 220. 

 1893. Cyprojiiscus, btobbing^ History ot L rusiacea^ p- 397. 

 1898. Cypronisciis, Sars, Crustacea of Norwa}', v(j1- 2, p- 232. 

 1900. Cyproiiiscus, Bonnier^ Travaux de \\ in\ereux, vol. 8, p. 



Sars gives the following delinition ui the genus: — 

 ■ iJody of the adult female forming an inert curved sac wholly 

 hlled with ova or embryos^ and affixed to the host .by the aid of a 

 thin llexible cord; dorsal face convex and exhibiting distinct 

 traces of segmentation, ventral face llattcucd. lateral parts ex- 

 panded, anterior extremity broadly produced, posterior obtusely 

 rounded and incurved- IJody of inuuature female sub-pyriform,. 

 bluntly truncated in front, hind extremity narrowly exserted? 

 lateral parts not distinctly defined. Body of young female, imme- 

 diately after the transformation subfusiform, ver\' faintly seg- 

 mented, front part still enveloped by the larval skin, and deeply 

 immerged within the body of the host, being anchored by a pair 

 of long, fiexuous, root-like processes. Adult male exactly re- 

 sembling the female larva of last stage, being rather slender, and 

 without eyes; hind expansion of basal joint of antennule divided 

 mto a restricted number of teeth, coxal plates coarsely pectinate;, 

 outer ramus of uropoda much smaller than the inner- Parasitic 

 on Ostracoda-" 



The single species for which the genus was founded, and on. 

 which the above definition is based, was originally described by 

 Sars in 1882 under the nanii ot Cryptotliiria cypridimiCy the 

 specimens havmg been found infesting Cxpn'diiM fiorvcgica, 

 Baird. So far as the material permits a decision, the new species 

 about to be described agrees accurately with the generic defini- 

 tion drawn up by Professor Sars, except in one particular. In 

 the new species the outer ramus of the iu-ii]wda is very little 

 smaller than the inner. 



In the male and last larval stage of female the type species 

 shows the terminal segment with an undivided margin. In the 

 new species the margin is divided into teeth. This character is 

 found also in the larval ]\'irasite of Acs^a vciitrosa, .M. Sars, de- 

 scribed by G- O. Sars as " Cryptoniscid \o. 2 " in the Crustacea 

 of Norway, vol- 2, p. 246. pi. 100, fig. 3. Further, in Hansen's 

 Isopoden. Cumaceen und Stomatopoden der Plankton Expedi- 

 tion, 1895. it appears clearly in the larvie which lie designates 

 EntoniscHs «, Bovh'iis ,1, Hopyrus 7, Bopynis , . That such a 

 peculiarity should be common to the parasites of Ostracoda, of 

 Isopoda, and of one or more higher Malacosiracan grottps, is 

 woriliv of notice, as one more link connecting the numerous 



