K0.2194. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 49 



Remarks. — It is unfortunate that the name of the host of this in- 

 teresting species was not known or at least was not recorded. Its 

 chief external distinguishing characters are the long and narrow 

 trunk, the long and w ide fourth thorax segment, and the split basal 

 plates of the legs. In the internal anatomy especial attention is 

 called to the exceptionally long ovaries, ^Yhich are conical, extend 

 nearly the entire length of the trunk, and taper to a sharp point pos- 

 teriorly. The oviducts are a little wider than the ovaries and also 

 a little longer, since they extend to the vulvae. The glandular por- 

 tion of the cement glands is relatively short and very indistinctly 

 segmented, the ducts are longer than the glandular portion and 

 straight. The intestine is comparatively narrow. 



Genus PERODERMA Heller. 



Perodcrnta Hellek, Eeise tier Fregatte Novara, 1S65, p. 250. 

 Taphrohin Corxalia, Attl della Societa Itallana di Scienze Naturall, voL 

 18, 1875, pt. 2, pp. 197-200. 



External generic characters of female. — Cephalothorax globular, 

 without horns but with a dense tuft of ramifying tubules on the 

 frontal margin of the head; the bases of these tubules are swollen 

 into flasks and their tips are somewhat tumid ; neck cylindrical, join- 

 ing the trunk at right angles about one-third the distance from its an- 

 terior end; trunk an elongated ovoid, narrowing posteriorly; egg 

 strings attached to the posterior end and four times the length of the 

 trunk, slender and straight; eggs numerous, uniseriate, and tightly 

 packed like a row of coins; no abdomen. 



First antennae three- jointed, setiferous; second antennae two- 

 jointed, chelate; proboscis short and conical, inclosing a pair of 

 mandibles; two pairs of maxillae, the second pair tippod w^ith stout 

 claws; three pairs of swimming legs, first two pairs close together 

 and biramose, third pair removed some distance and uniramose, all 

 the rami two-jointed and bearing plumose setae (adapted from Richi- 

 ardi, 187G). 



Internal generic characters of female. — No exact description can be 

 given through lack of material, but from the analogy of the new genus 

 CoUipravus (p. 78) it is certain that the insertion of the neck into the 

 side of the trunk instead of at the anterior end profoundly modifies 

 the arrangement of the generative organs and the digestive tube. 

 And hence the internal morphology, when obtained, will differ mnrk- 

 edly from that of Lernaeenicus, Sarcotretes, and Cardiodectes. But 

 since the neck is inserted in the center (laterally) of the trunk and at 

 right angles to its axis it does not seem probable that there will be 

 any disturbance of the bilateral symmetry, as there is in CoUipravus 

 and Phrixocephalus. 



77403— Proc.N.M.vol.53— 17 4 



