360 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



overlooked the prominent first antennae if they had been projecting 

 as Nordmann figures them. 



6. Nordmann's specimens were obtained from a species of Dlodon 

 found on the west coast of Africa while Kroyer's came from Dlodon 

 hystrix found in the Danish West Indies. 



Those described by the present author were taken from a Cliilo- 

 mycterus common in the Danish West Indies, and so closely related 

 to Dlodon that it was included under that genus until very recently. 



Furthermore they agree with Kroyer's specimen and dill'er from 

 those of Nordmann in every one of the above contrasted points. 



It seems practically certain, therefore, that Nordmann was describ- 

 ing a new species, and we may give for it the following 



SPECIKS DIAONORIS. 



Female. — Cephalothorax small and circular in outline, with emar- 

 ginate lappets. Free thorax fused into a rectangular body one-half 

 longer than wide, with rounded corners and straight sides. Genital 

 segment and abdomen very narrow and cylindrical, with prominent 

 anal lamina;. Egg-cases spindle-shapetl, shorter than the body and 

 much widened at the center. First antenna3 cylindrical, the same 

 diameter throughout, and projecting for their entire length in front 

 of the anterior margin of the cephalothorax. 



Four pits on the dorsal surface of the free thorax, the two anterior 

 much nearer the midline than the posterior. The entire body, 

 including the dorsal surface of the cephalothorax, but not the side 

 lappets, covered with small conical papilla3. 



(Verrucosus, covered with papilla^.) 



Genus ARTACOLAX Wilson. 



First thorax segment united with the head to form the carapace 

 which is much wider than it is long, and is squarely truncated pos- 

 teriorly. Second thorax segment free and as wide as the carapace or 

 nearl}^ so; third and fourth segments fused and but little narrower 

 than the second; third segment overlapping the fourth dorsally so as 

 to entirely conceal it. In lateral and ventral views the groove between 

 the two segments is still visible, but no motion is possible between 

 them. Fifth segment free and abruptly narrowed to a half or even a 

 third of the width of the preceding fused segments. Genital segment 

 enlarged but little; abdomen narrow and linear. The copepod has 

 thus a sort of tadpole shape, consisting of a much widened and 

 inflated anterior portion and a suddenly contracted and caudiform 

 posterior portion, quite different from the Cyclops form of the genus 

 Bomoloclms. First antennos six-jointed, the fused basal joints 

 enlarged and armed with stout setre; second antennfe four-jointed. 

 Mandibles with two joints in addition to the terminal cutting blade, 



