vol. 2, pt. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 93 



either be olongated, as in figures 77 and 78 oi fusiformis, or be shorter, 

 as in figure 81 of aspera. The only diagnostic feature of aspera is 

 the ridged and spinose character of the test in both solitary and 

 aggregated forms, and there is complete intergradation, even in those 

 characters, in my collections, between the smooth form and the most 

 spinose. For well-developed examples of Salpa fusiformis form 

 aspera see United States National Museum collections, Cat. Nos. 6439 

 and 6440. For individuals showing a character intermediate between 

 the form aspera and the smooth form see United States National 

 Museum collections: 



Cat. No. 145, U.S.N.M. (solitary and aggregated forms), Fish Hawk 

 station 1027, off Marthas Vineyard; September 14, 1881; 93 fathoms; 

 surface temperature, 65° F.; 10 ± specimens. 



Cat. No. 617, U.S.N.M. (aggregated form) , Albatross station D. 2575, 

 off Cape Cod; September 3, 1885; 1710 fathoms; surface tempera- 

 ture, 71° F.; 10 specimens. 



Cat. No. 6441, U.S.N.M. (solitary form), Albatross stations D. 5020- 

 5021, off Maryland; May 21, 1883; 179 fathoms; surface tempera- 

 ture, 54° F.; 4± specimens. 



Cat. No. 6442, U.S.N.M. (aggregated form), Fish Hawk station 925, 

 off Marthas Vineyard; July 16, 1881; surface temperature, 71° F.; 

 6+ specimens. 



Cat. No. 6613, U.S.N.M. (solitary form), Albatross station D. 5125, 

 Sulu Sea, vicinity of southern Panay, Philippine Islands; February 

 3, 1908; surface; surface temperature, 80° F.; surface density, 

 1.02444; 1+ specimen. 



Cat. No. 6583, U.S.N.M. (solitary form), Albatross station D. 5106, 

 China Soa, off southern Luzon, Philippine Islands; November 7, 

 1909; surface; surface temperature, 78° F.; surface density, 1.02393; 

 2 + specimens. 



SALPA CYLINDRICA Cuvier, 1804. 



Iasis cylindrica Savigny, 1816. 

 S. eoerulescens Chamisso, 1819. 



This species, while less common than Salpa fusiformis, is fairly 

 abundant and has been studied by a good many persons. Streiff, 

 who has done such accurate work on the musculature of other species, 

 has not studied this Salpa. 



Specimens of this species in the collections of the United States 

 National Museum are as follows: 



Cat. No. 6447, U.S.N.M. (solitary form), Albatross station D. 2542, 

 south of Block Island; August 7, 1885; 129 fathoms; surface tempera- 

 ture, 76° F.; 4 specimens. 



Cat. No. 2687, U.S.N.M. (aggregated form), off Newport, Rhode 

 Island; U. S. F. C, 1880; 75 + specimens. 



