322 DESCRIPTIONS OF PARASITIC COPEPODA. 



a subreniform shape, as represented ou i)late IX, fig, 2. The latter, in ven- 

 tral view, are convex on the outer margin and concave on the inner, 

 the outer terminal knob or lobe being the largest, and projecting further 

 back than the inner. 



The average length of adult specimens is about 5 or S.o'"'". The color 

 in alcohol is a yellowish or dingy white, the ovigerous tubes being of a 

 light yellow or yellowish bufi". 



This species is readily distinguished from the other species described 

 in this paper by the shape of the head, the small size of the anterior 

 antennae, the stoutness of the thoracic appendages, and the shape of 

 the posterior part of the body, including the genital segment and tail. 

 It has been collected only once, about 15 specimens having been taken 

 from nearly as many specimens of the common hake, Phycis tenuis, col- 

 lected off Martha's Vineyard, Mass., in 1883, by the U. S. Fish Com- 

 mission (G066). They were attached to the gills. Many of the speci- 

 mens are immature females, and nearly all were accompanied by a 

 single male each. 



Chondracanthus cottunculi, sp. nov. 



(Plate XI, figs. 1-7.) 



Of about the same size as Chondracanthus phycidis, but readily dis- 

 tinguished from both that species and G. galeritus by the size and shape 

 of the anterior antennae, and by other prominent characters. 



The greatest width of the body is equal to about one-half the length, 

 or slightly less. The head is considerably shorter than broad, about 

 one-fifth as long as the entire body, narrowed and rounded in front, the 

 lateral margins diverging rapidly and very convex and well rounded 

 posteriorly; the greatest width is just in advance of the hinder end. 

 The front margin is extended laterally in the shape of two rather promi- 

 nent rounded knobs; the dorsal surface arches strongly and terminates 

 posteriorly in a raised margin or collar ; on the ventral side, the lateral 

 margins are bordered by two broad, convex, smooth patches or cheeks. 

 The thorax is much constricted immediately back of the head, forming 

 a very short neck, from which the margins diverge very rapidly again 

 with a convex outline, producing a wing-like expansion on each side, 

 cut off squarely behind or, in some cases, sharply pointed and directed 

 more or less backward at the ends. This portion of tlie thorax is of 

 about the same width as the abdomen, to which it appears to belong, 

 but it gives origin to the second pair of thoracic appendages. 



The abdomen composes about three-fifths of the body in length, its 

 width being nearly three-fourths its length. It is moderately con- 

 vex dorsally, and consists of two segments with slightly raised margins. 

 The posterior segment is slightly longer than the anterior ; the postero- 

 lateral prolongations of moderate size, sometimes of nearly uniform 

 width with well-rounded ends, at others tapering and more pointed. 



