MICEONISCID^— CYPEONISCID^ 397 



The type, Microniscus fitscus, found by Mliller on a species 

 of Calami s on the coast of Brazil, is characterised by 

 having ' the third pair of thoracic feet longer than the 

 others, and terminating in an oval lamella, by which the 

 animal fixes itself on its host.' Microniscus caldni, Sars, 

 1882 (see Plate XVII.), with all seven pairs of feet 

 similar, fastens itself to the back of Calamus finmarchiciiSj 

 Gunner, and, according to Sars, also to Fseudocalanus 

 elongatus^ Boeck. It is possible, however, that the para- 

 sites on the latter Copepod have not been specially ex- 

 amined to' determine their identity with those on the 

 former. Microniscus calani has the pleopods two-branched, 

 a character which ' is only met with exceptionally in the 

 cryptoniscian embryo of the Entoniscida3 and the Bopyridae, 

 while it is the rule in the Cryptoniscidse.' 



Family 2. — C ijproniscidce. 



They are parasitic on Ostracoda. 



Gyproniscus, Kossmann, 1884. The characters of the 

 family and genus rest on those of a single species, Cypro- 

 niscus cypridince (Sars), 1882 (see Plate XVII.), which is 

 thus described : — ' The adult female, deprived of all the 

 mouth-organs and appendages, with the whole body filled 

 with eggs, sack-like, curved, the arched middle of the back 

 divided into six or seven indistinct segments, the ventral 

 side flattened, the sides slightly expanded, the frontal part 

 widely cordate, exserted, defined by an emargination on 

 either side from the lateral parts. The male (?Avhen adult) 

 like the female devoid of appendages, with the body 

 spindle-shaped, indistinctly segmented, the anterior ex- 

 tremity furnished on either side with a long flexuous root- 

 like process for fixation. An advanced larval stage re- 

 sembling Cryptothiria pygmcea in form and structure, but a 

 little more elongate, and quite without eyes.' Sars found 

 these queer animals at the Lofoden Isles fixed within the 

 valves of Cypridina norvegica^ Baird, to the hindmost part 

 of the animal's back, calmly occupying the space properly 

 belonging to the eggs of its host. As a rule he found what 



