VoL. 2] Ritter—The Pelagic Tunicata. 59 
since a comparison of my figures with that of Apstein will 
make them clear. It is worth noting that this adds another to 
the list of species in which the intestine of the aggregate genera- 
tion is in the form of a circle, these species being C. affinis, C. 
floridana and C. baker. 
The specimens of C. bakeri thus far obtained are few, and 
the variations in the muscle bands in these few suggest that fur- 
ther study of more ample material may modify somewhat the 
scheme given in the diagnosis; I cannot, however, believe that such 
modification can materially alter the results so far as concerns 
the definition of the species. In no species of salpa with which 
I have had experience have I found so much difficulty in tracing 
the muscles. This difficulty is due to the softness of the animal, 
and the extreme delicacy and transparency of the muscles them- 
selves. The separation of the muscles into body muscles on the 
one hand, and orifice muscles on the other, I recognize as being 
a particularly arbitrary matter in this species. For example, 
there would be almost as much reason for considering what I 
have enumerated as the first body muscle, a lip muscle; or, on 
the other hand, for calling what in my scheme is the third upper 
hp muscle, a body muscle. In fact, I have little doubt that what 
Apstein has designated number one in floridana corresponds to 
my third dorsal lip muscle. But the homologizing of the muscle 
bands in the different species of salpa is an exceedingly difficult, 
if indeed possible, thing; though comparison of the develop- 
mental stages would probably help in the matter. 
In all, about fourteen specimens of the species have been 
taken during the last three years, all on the coast of southern 
California, and all excepting one, which was taken in March, 
during the months of June and July. 
Cyclosalpa affinis (Chamisso). 
Salpa affinis Chamisso, 1819, p. 11, pl. figs. 2A-C, solitary genera- 
tion; 2D-H, aggregate generation. 
Cyclosalpa affinis Blainville, 1827. 
Salpa affinis Meyen, 1832, p. 407. 
Salpa affinis Traustedt, 1885, p. 357, Pl. I, figs. 6, 7, and 8. 
Cyclosalpa affinis Herdman, 1888, p. 86. 
Cyclosalpa affinis Lahille, 1890, p. 11. 
Salpa affinis Apstein, 1894, p. 4; Cyclosalpa, p. 24. 
