vol.2, pt. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 27 



None of the aggregated zooids show unusually long peduncles. In 

 none of the solitary individuals is the stolon sufficiently developed to 

 show buds, and the embryos in the aggregated zooids are much too 

 young to show muscles. These specimens bear the label Cat. No. 

 6432, U.S.N.M. (solitary form) Albatross station D 3901, Mokuhooniki 

 Islet, Pailolo Channel between Maui and Molokai Islands, Hawaiian 

 Islands, April 29, 1902; surf ace ; surf ace temperature 74° F.; 10 + 

 specimens. 



CYCLOSALPA AFFINIS (Chamisso, 1819). 



Plate 3 and plate 4, figs. 11 and 12. 



Salpa affinis Chammisso, 1819 (type). 

 C. affinis de Blainville, 1827. 

 C. affinis Herdman, 1888. 

 C. chamissonis Brooks, 1893. 



The following specimens of Cyclosalpa affinis are in the collections 

 of the United States National Museum: 



Cat. No. 6450, U.S.N.M. (solitary form) Albatross station D 2585, 

 off Cape May; Sept. 19, 1885; 542 fathoms; surface temperature 

 73° F; one specimen. 



Cat. No. 6451, U.S.N.M. (embryo) Albatross station 2749, south of 

 Block Island, Sept. 19, 1887; 705 fathoms; surface temperature 

 67° F. ; one specimen. 



Cat. No. 2833 U.S.N.M. (aggregated form) Albatross station D 

 2587, off Cape May; Sept. 20, 1885; 326 fathoms; eight specimens. 



Cyclosalpa affinis most resembles C. pinnata and is apparently its 

 nearest relative. In the solitary form the resemblance in shape of 

 body and character of test is close. Cyclosalpa affinis has no luminous 

 organs in either the solitary or aggregated forms. Only in Cyclosalpa 

 pinnata are luminous organs present in the aggregated form. They 

 are found in the solitary forms of C. pinnata, C.fioridana, C. bakeri, 

 and C. virgula, that is, in all species of Cyclosalpa except C. affinis 

 One naturally guesses that the depths in the ocean to which the sev- 

 eral species penetrate may be correlated with the presence or absence 

 of luminous organs, but we have little data for testing this surmise. 

 The greatest depths at which Cyclosalpae are certainly known to have 

 been taken are 55 meters (C. pinnata Ihle, 1910) and 500 meters (C 

 pinnata, subspecies polae Sigl 1912, b). Hauls with the vertical net, 

 collecting everything from the greater depths to the surface, 

 have sometimes contained Cyclosalpas, but we have no knowledge 

 of the horizontal strata from which the examples were taken. 

 Nor have we any data indicating that in Cyclosalpa floridana, C. bakeri, 

 and C. -virgula the solitary forms penetrate to greater depths than 

 the aggregated forms. Observations upon the vertical distribution 

 of the Cyclosalpas are to be desired. Since among the Cyclosalpas 



