92 PROCEEDINGS OP THE NATIONAL. MUSEUM vol. T2 



wider than the apertural sinus which is thin and linear. The form 

 appears quite variable, for that which we figure is a little different 

 from the opercula figured by Levinson, 1909, and by Waters, 1918. 

 We have never observed the apertural denticles described by Waters^ 

 1918. We believe that his specimen from Manaar is of another 

 species. 



Biology. — The larva scarcely chooses its substratum for it is affixed 

 to shells, bryozoa, corals, sponges, rocks, and fronds of small algae. 

 However, we have not yet observed colonies on nullipores. "The 

 color varies from translucent white or yellow to bright brick red ' 

 (Osburn) . 



This is a very fecund species, the frequency of specimens and the 

 abundance of ovicells being the immediate manifestations. This 

 fecundity has increased in time, for the ovicells of the fossil specimens- 

 are generally smaller than the ovicells of the recent specimens. 

 Reproduction was observed during the first 

 three months of the year. 



An ordinary polypide constructs the zooec- 

 ium. It degenerates and is replaced by a female 

 polypide which constructs the ovicell above the 

 distal zooecium and the aperture. It is deprived 

 of tentacles which could not emerge through the 

 ^ special orifice of the ovicell. The passage of the 



Fig 14.— Stylopoma spon- • au j • i, i j. j? u- „ 



GiTEs Pali AS 1766 A. ®Sgs IS thus assurcd m an absolute fashion. 



Mandible of an inter- The cscapc of the larvae operates as in other 



rERcuL u™'^'"'''''" ^' species by the rupture of the membrane which 



closes the ovicell. 



Occurrence.— Albatross Station D. 2319, north of Cuba; 23° 10' 2>1" 



N.; 82° 20' 06'' W.; 143 fms.; gray coral. 



Albatross Station D. 2320, north of Cuba; 23° 10' 39" 



N.; 82° 18' 48" W.; 130 fms.; fine coral. 

 Albatross Station D. 2405, Gulf of Mexico; 28° 45' 00" 

 N.; 85° 02' 00" W.; 30 fms.; gray sand, broken 

 coral. 

 Florida, 21-56 meters (Smitt); Tortugas, 5-29 meters 



(Osburn) . 

 Pliocene: Minnitimmi Creek, Bocas Island, Almirante 



Bay, Panama. 

 Caribbean Sea, St. Thomas and St. John (Levinsen); 

 Bermuda (Verrill); Cape Verde Islands, 16 meters 

 (Waters) , and perhaps Ceylon (Thornely) and Malacca 

 (Levinsen). 

 Geologic distribution. — Upper Miocene of Virginia to Florida; Plio- 

 cene of Florida; Pleistocene of South Carolina, Florida, and Panama. 

 Plesioty pes. —Cat. Nos. 7600, 70861, U.S.N.M. 



