17-1: TWELFTH ANNUAL REPORT. 



one being a small bristle. The male antenna is of peculiar form. 



The teeth of the anal plate are large and emarginate (see fig. 4.) 



The swimming feet are all armed with very strong spines, aside 



from the usual quota of spines at the end of each joint. Length 



.65 mm. 



NOTi.— C. /ronfinaiis, Rehberg. This author seems to have parted with his usual 

 acumen in the remarks upon this species. After describing a Gauthocaniptus witli the 

 inner ramus of the first foot "reichlich doppeltso lang wie die beiden (Irundglieder de« 

 Aussennasts," he draws a moral on the mutability of genera from the fact that Brady 

 founded the genus Attheyella "auf grund der Eingliede des inneuastes am fierten 

 Fusspaare und einer derartigen Bildung des ersten Fusses, wie er bie C. frontinalis 

 beschreiben ist." Brady says (Bi it. Copepoda, p. 58) : "inner branch of first pair of feet 

 scarcely at all elongated, and either 2- or 3-jointed," etc. The distinctive characters 

 being the 1- or 2-jointed 2d and 3d feet and the 1-jointed inner ramus of the fourth foot, 

 it Is doubtful if C. frontinalis is really new. 



II. Gekus Attheyella, Brady. 



This genus, the diagnostic characters of which have been above 

 indicated, contains three nominal species. It is quite difficult to 

 say what differences exist between Sars' '''Canthocamptus''' pygmcBUS 

 and Attheyella spinosa. Brady did not seem to recognize the fact 

 that his diagnosis included that species. The third species is the 

 blind A. cyrptorum, of Brady, which it is interesting to compare 

 with the blind Bradya limicola of the coast of the gulf of Mexico. 



P(ECILOSTOMATA. 



This group, consisting of animals more or less like Cyclops in 

 appearance, but, during part of their existence, semi-parasitic, has 

 been very little studied in America. Most of the fresh-water species 

 inhabit the gill-cavities of fishes. The gills of fishes should always 

 be examined (if practicable, microscopically) for these interesting 

 animals. 



The mouth parts are greatly reduced and their homologies un- 

 certain. 



Genus Ergasilus, Nordmann. 



Body shaped much as in Cyclops; anterior antennae short; anten- 

 nules in the female large, four-jointed, terminating in a strong 

 claw. Mouth opening in the center of the very large head, which 

 is not beaked in front. The mouth parts are inconspicuous, but 

 the maxilliped is a stout organ terminating in a long claw. The 

 three anterior pairs of feet are bi-ramose, and each ramus is three- 



