NO. 1788. NORTH AMERICAN ERGASILID^— WILSON. 381 



maxillse apparently lacking; second maxillse stout and simple, the 

 terminal joint covered with hairs; maxillipeds similar to those of 

 Bomolochus, but without plumose setse. First swimming legs with 

 flattened rami; both rami of the second, third, and fourth legs three- 

 jointed, the exopods not well supplied with setse. Fifth legs unira- 

 mose, two-jointed; rudimentary sixth legs on the genital segment. 

 Egg-cases short and narrow; eggs large, only about thirty in each 

 case. 



Type-sj)ecies. — Pseudoeucanthus alosse. Brian, 1906. 



(Pseudoeucanthus , pseudo, false and Eucantlius). 



There are several points in the description of this genus that need 

 confirmation or correction. In the first place, Brian himself places 

 a question mark after the sex of his specimens. The only thing in the 

 anatomy of the individual he has figured as a "male(?)" which sug- 

 gests that sex is the lack of egg-strings. On the contrary, the genital 

 segment is exactly the same as in the female and the maxillipeds are 

 turned forv/ard outside the other mouth-parts instead of being in 

 normal position behind them. 



Again, Brian has failed to discover any first maxillae, although he 

 found them in Bomolochus and AncJiistrotos , described in the same 

 paper, and he says nothing about them in the text. If this pair is 

 really lacking that would constitute a generic distinction stronger 

 than any he has advanced. 



Finally, in the figure he has given there are only tlu-ee free segments 

 in front of the genital segment, but there are the usual four pairs of 

 legs. From the arrangement of the latter it is impossible to tell 

 which two of the segments are fused. Until these points of vital 

 importance are settled the genus must be left as Brian has described 

 it. 



Body strongly flattened; head fused with the first thorax segment 

 and the resultant cephalothorax reentrant on the ventral, surface, so 

 that its lateral margins with the basal joints of the first antcnna3 and 

 the first legs form an effective prehensile disk as in the Bomolochinae. 

 All the other thorax segments are free; the genital segment is not 

 enlarged; the abdomen is cylindrical and tapers gradually, producing 

 a typical Cyclops form like that of the Ergasilinse. First antennae 

 cylindrical, the basal joints enlarged but little, and usually not 

 flattened; second antennae similar to those in the Bomolochinae. 

 First swimming legs flattened, rami wide and with only one or two 

 joints; the other legs of the usual pattern. Male considerably 

 smaller than the female, with the ordinary sexual differences in the 

 second antennae and second maxillipeds. Species averaging some- 

 what larger than the Bomolochinae, 2 to 2.5 mm. in length. 



