37 



especially unusually strong, with the terminal part reflexed and armed with long 

 claw-like spines. Oral parts in male much degenerated. Natatory legs power- 

 fully developed, and on the whole resembling in structure those in the ^Etideidce. 

 5th pair of legs wholly wanting in female, those in male exceedingly large and 

 powerful. Ovisac / present in female. 



Remarks. This family as yet only comprises a single genus, viz., Euehceta, 

 Philippi, which, however, exhibits some very conspicuous structural differences from 

 the other Amphascandria. The genus was also regarded by Dr. Giesbrecht as 

 the type of a particular subfamily, Euchatince, which I now propose, in accordance 

 with the plan followed in this account, to raise to the rank of a true family. 



Gen. 10. EUChaeta, Philippi, 1852. 



Generic Characters. Body comparatively slender, especially in the male, 

 with the cephalosome attenuated in front, rostrum pointing in female obliquely 

 forwards, in male more downwards, and having at the base in front a more or 

 less projecting ledge. Lateral corners of last segment of metasome rounded off, 

 and generally densely clothed with hairs below. Urosome. as a rule, more elongated 

 than in the ^Etideidce, genital protuberance in female very prominent, and of 

 different form in the different species. Caudal raini in female firmly connected 

 with the last caudal segment, in male mobile, marginal setae spread in a fan-like 

 manner and beautifully plumous, the innermost but one much longer than the 

 others, appendicular bristle generally very slender, hair-like and geniculate at the 

 base. Eye small, subventi al. Anterior antennae in female 24-articulate, 3rd, 7th, 

 8th and 13th articulations each carrying an unusually long bristle at the end 

 anteriorly; terminal articulation very small, with a long reflexed seta on the tip. 

 Epistome produced in front of the anterior lip to a knob-like, densely hirsute 

 projection. Anterior maxillipeds with the spines of the terminal part very strong, 

 claw-like. Posterior maxillipeds with the 2nd basal joint very large, fusiform, 

 attenuated distally. Both pairs in male much reduced in size. 1st pair of legs 

 .much smaller than the others, and having the first 2 joints of the outer ramus 

 confluent in female. Inner ramus of the first 2 pairs of legs uniarticulate, of the 

 2 succeeding pairs 3-articulate. Both legs of last pair in male well developed; 

 right leg with a long styliform inner ramus, outer ramus biarticulate, with the 

 distal joint claw-like; left leg terminating in a complicated hand, by which the 

 spermatophore is seized. 



6 Crustacea. 



