vol. 2, ft. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 57 



zooids. Dober (1912) gives a figure of a form which he names 

 Salpa amboinensis, but from the character of the intestine, only 

 faintly delineated, it seems to be Ritteria retracta. Both solitary 

 and chain forms of R. amboinensis are known. As Ihle has shown, 

 it is clearly distinct from R. retracta, though the musculatures of the 

 solitary forms of the two species are very much alike. The gut is 

 very different in the two. 



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Fio. 29.— Ritteria amboinensis, solitary form, viewed from the left side, x 5 diameters. From 

 Ihle (1910). The oral muscles are slightly changed from Ihle's drawing 



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a.o. 



Fio. 30.— Ritteria amboinensis, solitary form, dorsal view, x 4J dumeters. (Drawn by Hoyt 



S. HOPKiNS.) 

 RITTERIA AMBOINENSIS, solitary form. 



Ihle's figure of a left side view of this form (fig. 29) can best be 

 used for comparison with the other Ritterias. Compare also our 

 figure of a dorsal view (fig. 30). 



There are 10 to 13 body muscles and a dorsally incomplete inter- 

 mediate muscle. According to Apstein (1904), in the embryo the 

 intermediate muscle is complete dorsally, being united to body 



