78 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



APSTEINIA ASYMMETUICA (Fowler, 189G). 



Salpa asymmetrica Fowler, 1896. 



This species, described by Fowler, has been observed also by 

 Apstein (1901). I have had no specimens. 1 Dober (1912) figures 



the nervous system, but 

 without detail in the 

 eye, so no use can be 

 made here of his work. 

 Details of the structure 

 of the oral and atrial 

 muscles are not in- 

 cluded in these descrip- 

 tions, nor is the char- 

 acter of the eye suffi- 

 ciently known for com- 

 parisons. 



APSTEINIA ASYMMETRICA. 

 solitary form. 



Judging from Ap- 

 stein's figure (fig. 58), 

 interpreted with tho aid 

 of Fowler's side view of 

 the embryo (fig. 59), 

 there are apparently 10 



From Metcalf and Johnson body muscles, though 



the tenth very possibly 

 series. The intermediate muscle and body 



FIG. 57.— APSTEINIA PUNCTATA, 

 SECTION OF GANGLION AND EYE3. 

 (1905). 



AGGREGATED ZOOlD, SAGITTAL 



i.m. 



"& 



belongs to the atrial 

 muscles I and II are in contact dorsally, 

 so also are body muscles III and IV and 

 VIII and IX. The gut is described as a 

 compact "nucleus." 



One interesting feature of the oral mus- 

 culature is observed in Fowler's figures. 

 There is on each side a strong oral re] 

 tractor muscle, which posteriorly is bifur- 

 cated, as in Ai)steinia punctata, into 

 dorsal and ventral portions. The ventral 

 division extends back to the filth body 

 muscle; the dorsal division reaches past 

 all the body muscles to the atrial sphinc- 

 ters. The resemblance to Apsteinia 

 punctata is very marked and is a very clear 



indication of the affinity of the two species, fio. ss.-apsteinia astmmetrica, em 

 Fowler's description and figures are ob- BRYO - D0RSAL yTKW - x 22 d " m eters 



a.o. 



From Apstein (1901). 



1 Specimens obtained after this paper was in press are described in the Appendix, see page 183. 



