ART. 5. NORTH AMERICAN PARASITIC COPEPODS WILSON. 81 



(buccatus, large- jawed, alluding to the maxillipeds.) 



Remarks. — When removed from their host these parasites float in 

 water, and even in alcohol, and it is very difficult to wet the outside of 

 their bodies. So long as they remain alive they snap their maxilli- 

 peds viciously together in an endeavor to fasten to something. If 

 a gill filament or similar fragment be left in the watch glass with 

 them, they will all find it and fasten to it. They can not swim, but 

 by wriggling their bodies in a manner similar to that of the mos- 

 quito larva they can propel themselves slowly, but such motion is 

 entirely aimless, since they can not control its direction at all. 



This species differs in many particulars from appendiculatus and 

 when the male is discovered it is possible that it will demand a new 

 genus for its reception. Its general make-up, however, is very much 

 like that of the present genus, and it may be left here until the male 

 is discovered. 



The swimming legs are even more degenerate than those of appen- 

 diculatus; the fourth pair have entirely disappeared, and the first 

 pair can be located only with the help of structures beneath the skin. 

 The maxillipeds are different from anything heretofore found in 

 that the basal joint is partly divided lengthwise. 



Genus HATSCHEKIA Poche. 



Clavella Kr0yee, Natiirhistorisk Tidsskrift, vol. 1, 1838, p. 196. 



Clavella Milne Edwards, Histoire Naturelle des Crustac^s, 1840, vol. 3, p. 



494. 

 Clavella P. J. van Beneden, Ann. des Sci. Nat., ser. 3, vol. 16, 1851, p. 99. 

 Cycnus Hesse, Ann. des Sci. Nat., sev. 6, vol. 8, 1878, art. 11, pp. 1-34, pis. 



19-21. 

 Clavella T. Scott, 18th Ann. Report Fishery Board, Scotland, 1900, p. 159. 

 Clavella Brian, Atti Soc. Ligustica Sci. nat. e geog., vol. 13, 1902, p. 37. 

 Hatscliekia Poche, Zool. Anz., vol. 26, 1902, p. 16. 

 Hatschekia T. and A. Scott, British Parasitic Copepoda, 1912, p. 112. 



Generic characters of female. — Head and thorax separated, the 

 former small and usually rounded. First two thorax segments more 

 or less free, but often fused with each other, each with a pair of bira- 

 mose swimming legs. The remainder of the thorax, including the 

 genital segment, fused into a subcylindrical trunk, elongate and nar- 

 row. Abdomen short and one-jointed or lacking ; anal laminae minute 

 with tiny setae. 



First antennae small, filiform, three to six jointed, tlie joints often 

 indistinct. Second antennae short and stout, with strong terminal 

 claws, and often with an accessory spine at the base of each antenna. 

 Mandibles and first maxillae small, the latter as tiny knobs at the 

 sides of the mouth, armed with spines. Second maxillae apparently 

 lacking, maxillipeds slender and uncinate. 



