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



95 



Cat. No. 6624, U.S.N.M. (aggregated form), Albatross station D. 

 5155; Sulu Archipelago, Tawi Tawi Group; February 19, 1908; sur- 

 face; surface temperature, 81° F.; 1 specimen. 



SALPA CYLINDRICA, solitary form. 



In the general shape of the body the solitary form of Salpa cylindrica 

 (fig. 82) resembles that of other species of the true Salpas. The nine 

 body muscles are all continuous dorsally across the mid line. Ven- 

 trally they all extend farther down than in Salpa maxima or S. fusi- 

 formis, but do not reach the mid-ventral line. Body muscles I to IV 

 are in contact dorsally. As in the other true Salpae, the intermediate 

 muscle is associated with the oral muscles rather than the body 

 muscles. 



There is a single oral retractor muscle, which gives rise directly to 

 the two sphincters of the lower lip and is in contact with the basal 

 ends of the admarginal sphincter of the dorsal lip. A second, broader 

 sphincter of the upper lip passes inside the oral retractor muscle, just 



JX J2ZT M 



a.o. % 



Fig. 82.— Salpa cylindrica, solitary form, viewed from the right side. X 6 diameters. fr<>m 

 Hitter (1905) with modifications. 



in front of the intermediate muscle. The short dorsal longitudinal 

 muscle of the oral series is not in contact with the oral sphincters or 

 the intermediate muscle, but is independent. 



There is a well-developed atrial retractor muscle on each side, 

 similar to the corresponding muscle of Salpa maxima. The arrange- 

 ment of the atrial sphincters is also somewhat similar in the two 

 species. 



The gut is a compact " nucleus," as in the other true Salpas. The 

 stolon is straight, lying below the endostyle. The eye is in the usual 

 horse-shoe form. The neural glands and their ducts are in the usual 

 condition, but there are no outgrowths from the ganglion 



SALPA CYLINDRICA, aggregated form. 



This form (figs. 83 and 84) has hollow conical anterior and posterior 

 protuberances from the body, slightly asymmetrically arranged. 

 Some specimens show irregular connective tissue fibers in the ante- 

 rior protuberance, reaching to its tip. At the base of the protuber- 

 2621— Bull. 100, vol. 2—19 7 



