1914.] NATURAL ttClKNCES OF PHILADELPHIA. 57 



The antcnnules are characterized by the two very short terminal 

 segments. 

 . The armature of the three-jointed swimming feet is as follows: 



First pair — outer i:Amus, three spines, five setae; inner ramus, one 



seta, one spine, four setae. 

 Second pair — outer ramus, four spines, five setae; inner ramus, one 



seta, one spine, four setse. 

 Third pair — like the second pair. 

 Fourth pair — outer ramus, three spines, five setae; inner ramus, one 



seta, two spines, two setae. 



The inner margins of all the branches of the swimming feet are 

 ornamented with rows of bristles. This is especially the case in the 

 second, third, and fourth pairs. In her description of the variations 

 of this species, Miss BjTnes says: " The most striking variation iir 

 C. fimhriatus is a tendencj^ toward a reduction in the armature of 

 the inner ramus of the first swimming feet, where in the apical 

 position, for example, a single large spine replaced two setae or a 

 spine and a seta, which is the typical armature of the organ." She 

 does not give the ''typical armature" in her table, and the small seta 

 on the inner side of the inner ramus of the first pair of swimming 

 feet she has probably overlooked. 



The fifth foot (fig. 8, PI. IV), which is one-jointed, I find bearing 

 the following armature: On the inner side of the distal end of the 

 single segment there is a heavy spine, serrate on its inner surface 

 and finely but not densely plumose on its outer margin. The row of 

 minute serrations which Schmeil shows to be present in the type 

 form at the base of the corresponding spine (see his Taf. VII, fig. 12) 

 I do not find at all after a careful examination of a number of speci- 

 mens. There is a single spine-like projection at the base of the 

 inner spine, but no indication of a row. On the outer distal corner 

 of the fifth foot there is a very coarse spine-like seta that is densely 

 plumose on its inner and outer side. These two "spines" (the 

 outer is more nearly a spine than a seta) are of equal length. Between 

 them and borne at the end of a button-like process is the middle 

 seta, slightly longer than the two spines and plumose on its distal 

 half. Rehberg noted that "das rudimentare Fiisschen ist mit zwei 

 gleichlangen Dornen und einem kiirzeren Haar Isesetzt, wahrend 

 sich bei Cycl. fimhriatus nur ein kurzer Dorn und zwei lange Haareii 

 befinden." Schmeil admits that Rehberg's description and drawing 

 is quite accurate, states, however, that the fifth feet in type and 

 variety are identical. I am inclined to agree with Rehberg that 



