CALCARELLA. 89 



in front; columella rather straight; outer lip acute, the 



margin entire. 



Ex. M. pelagica, Forbes, pi. GO, fig. 3. Operculum, 

 M. pelagica, fig. 3, a, 3 b. Shell, M. spinigera, A. Adams, 

 fig. 3, c. 



The species on which this genus is founded was taken in 

 the towing-net by Mr. Macgillivray off the East coast of 

 Australia, fifteen miles from the shore. They were observed 

 to be associated together in considerable numbers. The M. 

 spinigera was also captured by one of the Authors, floating 

 gregariously in the middle of the Mindoro Sea. The 

 Struthiolaria microscopica of Gray, described in Beechy's 

 "Voyage," is, perhaps, the same shell as M. pelagica, Forbes. 



Species of Macgillivrayia. 



pelagica, Forbes. straminea, A, Adams. 



spinigera, A. Adams. 



Genus CALCARELLA, Souleyet. 



Shell sub-globose, horny, pellucid; whorls three, flat above, 

 bicarinate, apex mamillated, last whorl strongly tri-carinate, 

 keels wide apart, armed with regular, acute, triangular spines; 

 aperture triangular, internally semilunar and thickened ; 

 inner lip thickened, convex in the middle, sinuous an- 

 teriorly; outer lip tri-spinose. 



Ex. C. spinosa, Souleyet, pi. 69, fig. 4, 4, a. 



The little shells on which this genus is founded are pela- 

 gian, having been discovered by M. Souleyet in the South 

 Sea, during the voyage of the Bonite. A similar form was 

 detected by one of the Authors, associated with specimens of 

 Macgillivrayia spinigera, floating on the surface of tin- 



