vol. 2, pt. 2] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 35 



peduncle where it forms the anterior half of the single muscle. The 

 third body muscle and its branches show a combination of charac- 

 ters which appear separately in C. pinnata and C. affinis, though noth- 

 ing not found in one or the other of these species. From its upper 

 part arises the atrial sphincter. (See last body muscle in C. pinnata.) 

 The posterior branches of these muscles on the two sides of the body 

 unite on the mid line below the base of the atrial siphon, and are 

 continued on the mid line downward into the base of the postabdo- 

 men, stopping in the bend of the intestine, thus resembling C. affinis. 

 From the lower end of the third muscle, on each side, arises a small 

 strand, which curves backward and upward also into the post- 

 abdomen, as in C. affinis. This muscle on the left side is continued 

 into the tubular portion of the postabdomen. On the right side 

 its fellow ends near the enlargement referred to as a rudimentary 

 stomach. Note that this third body muscle with its connections 

 resembles not the third but the fourth body muscle of C. pinnata and 

 C. affinis. 



As in the solitary form, the atrial sphincters are few in number. 

 The oral muscles are simpler than in the solitary form of this species 

 or either form of C. pinnata or C. affinis. There is a single oral retrac- 

 tor running forward from the first body muscle. This divides ante- 

 riorly into three dorsal and three ventral branches forming the three 

 sphincters of the dorsal and the ventral lips respectively. 



The upper lip in both forms of this species is the larger externally, 

 but the lower lip is enlarged internally and shows the same type of 

 valve structure described for Cyclosalpa pinnata. 



The gut is a little more curved than in C. affinis, the intestine cross- 

 ing the esophagus so that the anus is behind and above the esopha- 

 geal aperture. There is no caecum, but, as in the aggregated Cyclo- 

 salpa affinis, there is an enlargement of the intestine just behind its 

 union with the esophagus. This stomachlike enlargement is greater 

 than in C. affinis. The intestinal gland is present in the usual form, 

 but to avoid the confusion of too many lines it is not shown in our 

 figures. 



The testis, instead of lying along the intestine as in Cyclosalpa pin- 

 nata and C. affinis, pushes out far behind the body, completely filling 

 a long conoidal evagination of the mantle. Its duct passes above the 

 intestine, through its loop, to open dorsal to the anus. The ovary 

 lies just behind the last body muscle, instead of in front of it, as in 

 C. pinnata and C. affinis. Its duct, however, passes forward, as in 

 these latter species, to a point behind the next to the last body muscle. 

 The heart has the usual position. The simple outline of the aperture 



