233 



larval skin, and deeply immerged within the body of the host, being anchored by 

 a pair of long, flexuous, root-like processes. — Adult male exactly resembling the 

 female larva of last stage, being rather slender, and without eyes; hind expansion 

 of basal joint of antennulse divided into a restricted number of teeth, coxal 

 plates coarsely pectinate; outer ramus of uropoda much smaller than the inner. 

 Parasitic on Ostracoda. 



Remarks. — This genus was established in the year 1884 by Dr. Kossman, 

 to include the peculiar parasite briefly described and figured by the present 

 author in his „Oversigt" as Cryptothiria cypridinw. I now fully admit that this 

 form ought to be regarded as the type of a distinct genus, but cannot, on the 

 other hand, agree with MM. Griard and Bonnier, that the parasitism of this form 

 on an Ostracod should make it necessary to place it even in a separate family. 

 The structure of the male and the last larval stage of the female do not exhibit 

 any essential differences from those found in other Cryptoniscidce. The genus 

 comprises as yet only a single species, to be described below. 



Cyproniseus eypridinae, G. 0. Sars. 

 (pi. xcvn, pi. xcvin, fig. l). 



Cryptothiria cypridince, G. 0. Sars. Oversigt af Norges Crustaceer I, p. 13, PI. 2, figs. 17 — 21. 



Specific Characters. — Body of adult female almost semi-globular in 

 shape, with the dorsal face greatly vaulted, the ventral one concave, anterior 

 extremity, toning forward in relation to the host, subcordiform, posterior nar- 

 rower and inflexed, obtuse at the tip. Dorsal part of body well defined from 

 the lateral parts, and divided by distinct transversal lines into 7 segments, each 

 forming an obtuse gibbosity; lateral parts moderately expanded and unsegmented. 

 Integuments very thin and pellucid, without any obvious opaque area dorsally. 

 — Immature female somewhat varying in form, more generally clavate, with the 

 dorsal margin more or less deeply indented between the segments, posterior 

 extremity narrowly exserted and deflexed, lateral parts not defined from the 

 dorsal. — S_till_ younger, female, immediately after the transformation, fusiform, 

 but. slightly curved with the ventral face very convex in front, neck constricted 

 and__still- covered by some of the anterior segments of the larval skin, cephalic 

 part wholly immerged within the skin of the host and exhibiting in front a 

 strongly denticulated recurved projection, root-like filaments long and flexuous. 

 Male (and female in last larval stage) long and slender, sublinear, with the 

 dorsal face finely striolate transversally. Cephalic segment evenly rounded in front; 



30. Crustacea. 



