462 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



This is a comparatively delicate species, less heavily calcified than 

 most members of the genus and all of the many colonies observed are 

 small (usually less than 5 mm in diameter), but the aperture and its 

 appended organs, the nature of the frontal and the characters of the 

 ovicell ally it with Rhynchozoon. 



Described from the Tortugas Islands, Florida, and later recorded 

 from Curagao Island, Porto Rico, and Caledonia Bay, Panama. Canu 

 and Bassler have described a similar species R. levigatum (1923:157) 

 from the Pleistocene of Panama, which appears to differ only by its 

 larger size and smoother frontal surface. 



Hancock Stations: 129-34, Braithwaite Bay, Socorro Island, west 

 of Mexico; 219, Clarion Island, west of Mexico; and San Benito Islands, 

 west coast of Lower California, 13 to 18 fms. The Pacific coast speci- 

 mens agree in all details with those from the Gulf of Mexico and the 

 Caribbean Sea. 



