80 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Ritterias. The oral retractor muscle so resembles that of Apsteinia 

 punctata as to indicate close relationship between that species and 



a. a 



int. 



A 



3 



Fig. 60.— Apsteinia asymmetrica, aggregated form: A, dorsal view; B, ventral view 



X 22 DIAMETERS. FROM APSTEIN (1901). 



A 



B 



Fig. 61.— Apsteinia asymmetrica, aggregated zooid: A, ventral view; B, dorsal view 

 X 4J diameters. From Fowler (1896). 



A. asymmetrica. The very marked asymmetry of the aggregated 

 zooids separates this species from the true Salpae, sensu strictu. 



