.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 143 



This is seen in the muscles, which are equally reduced in the two 

 phases of the life history. The gut also is in the same condition in 

 the two. 



In both forms of Pegea, as in Thetys vagina and Iasis zonaria, all 

 the rod-cells in all the eyes of the aggregated zooids are irregular 

 and degenerate. 



Traustedtia, new subgenus. 



This subgenus includes the most highly modified members of the 

 family. It has been studied by Quoy and Gaimard (1826-1834), 

 Traustedt (1893), Apstein (1894, b, 1904, 1906, b) and Dober (1912). 

 Ihle (1911) discusses briefly 

 the nomenclature. In Ap- 

 stein's several accounts two 

 species seem to be confused. 

 Our specimen aids little in 

 clearing up this confusion. 

 All the material previously 

 known should be restudied. 

 The Traustedtias are rare 

 forms and new material is 

 not likely often to be found 

 or to be abundant when 

 found. Assuming the gen- 

 eral accuracy of the descrip- 

 tions that have been pub- 

 lished, I am tentatively recognizing two species — multitentaculata and 

 radiata. We have had only a single specimen of the solitary form 

 of the species multitentaculata. This will first be described. It is 

 different enough from Apstein's specimen to be placed in a distinct 

 subspecies. The species multitentaculata may be taken as the type 

 of the subgenus since it was the first described and its aggregated 

 form is known. 



TRAUSTEDTIA MULTITENTACULATA, new subspecies B1CRISTATA, solitary form. 



Plate 14. 



The United States National Museum collections contain a single 

 example of the solitary form of this very rare salpa. Cat. No. 6430 

 (Type) U.S.N.M.; (solitary form), Albatross station D. 2585, off 

 Marthas Vineyard; September 19, 1885; 542 fathoms; surface tem- 

 perature, 73° F. It was collected at the surface of the ocean, along 

 with very many solitary and aggregated zooids of Thalia democratica, 

 among which we found it, in a large bottle containing several thou- 

 sand Thalias. The specimen, 7.5 mm. long, is in perfect condition, 

 being excellently preserved in picric acid and alcohol. We have 

 2621— Bull. 100, vol. 2—19 10 



Fig. 132.— Pegea confederata, subspecies bicaudata, 

 aggregated form, oblique vertical section of the 

 ganglion, optic nerve and one half of the dorsal 

 eye. x 180 diameters. from metcalf (1893, c). 



