vol.. -M'T. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 119 



Our collections from the Philippines, on the other hand, contain 

 numerous individuals of the prevalent Atlantic type, having the 

 mantle protuberances few in number (though rather too long to be 

 characteristic), having thelobesof the testis subdivided into numerous 

 lobules, and having the test behind the intestinal "nucleus" pointed 

 instead of rounded. There seems to be rather complete intergrada- 

 tion between the two types. It seems hardly worth while to give 

 them distinct varietal names. 



From study of the smallest (youngest) of the aggregated zooids 

 of the Philippine type one point of interest in the development of 

 the eye is seen. In an early stage of its development, those portions 

 of the eye marked e\ and e 2 in figures 110, 111, and 112, are united 

 into one, and the eye is thus in two instead of three divisions. In 

 Cyclosalpa pinnata buds the eye is at first horseshoe-shaped, the 

 hollow of the horseshoe soon becoming filled; later the posterior 

 portion of the inverted disk becomes again divided into two limbs. 

 In Thalia democratica the latter two stages are the only ones I have 

 found, the eye of the aggregated zooid appearing, in the earliest 

 stage I have seen, as a disk not a horseshoe. In other species of 

 Salpidae the final stage, involving splitting of the posterior part of 

 the inverted disk into two limbs, is omitted. 



THALIA LONGICAUDA (Quoy and Gaimard, 1824). 



Salpa longicauda Quoy and Gaimard, J 824. 



S. democratica-mucronata, var. Jlagellifera Traustedt, 1885. 



S . flagellifera Apsteik, 1894, a. 



Of this species I have had no specimens. It is very similar to 

 Thalia democratica, being distinguished by the presence of two 

 unusually long and slender appendages from the posterior angles 

 of the body in the solitary form (fig. 113); by having the body 

 muscles not continuous across the ventral line in the solitary form; 

 by the independence, in the solitary form, of all the body muscles, 

 which are not united dorsally into two groups as in the solitary 

 Tfudia democratica; and by the fact that in the aggregated individuals 

 the intermediate muscle and body muscles are composed of more 

 fibers than they are in Thalia democratica. Apstein (1906, a and b) 

 gives the numbers as follows (using my notation). 



Thalia Thalia 



democratica longicauda 

 Body muscle: fibers. fibers. 



1 5 8-11 



II 3-4 6-9 



III 3 8-9 



IV, a :i-4 5-7 



IV, b 2 2 



Apstein's body muscle V is here counted as the posterior branch 

 of the body muscle IV. 



