46 ALLAN HANCOCK ATLANTIC EXPEDITION REPORT 



tubercles on its summit in complete calcification. A rather large, round 

 oral avicularium is situated immediately above the primary orifice, but 

 this is often wanting. Small rounded avicularia, measuring only 0.05 to 

 0.07 mm, occur in various positions on the frontal. 



The ovicells, as in the other species of the genus (T. turrita Smitt and 

 T. protecta Osburnj^ are complete (not widely open as in Holoporella), 

 very large (0.45 to 0.50 mm in breadth) and covered by a tremocyst 

 similar to that of the frontal. There is no evidence of the large central 

 pore which is present in the other species, but the specimen is heavily 

 calcified and it may have become covered as happens in later stages of 

 turrita and protecta. The ooecial aperture opens into the peristome and 

 is not closed by the operculum. 



In the writer's collection there are several specimens from Porto 

 Rico, which for lack of the ovicells were not reported in his Porto Rico 

 paper (1940). 



Distribution. — Station At533, 5 miles NW of Galera Point Light, 

 Colombia at 12 fms, one colony of 24 zooecia in reproduction, attached 

 to a coralline. 



Family Mamilloporidae Canu and Bassler 1927 



Genus MAMILLOPORA Smitt, 1873 



Mamillopora cupula Smitt, 1873 



Smitt 1873 : Z3>. Canu and Bassler 1928 : 153. 



There are three cup or saucer-shaped genera in the West Indian 

 region, Cupuladria, Discoporella and Mamillopora, all belonging to dif- 

 ferent families. What they have in common is chiefly the habit of the 

 larva in attaching itself to a sand grain or other small particle and devel- 

 oping an unattached colony which may have some small capacity for 

 movement by means of the avicularia or vibracularia. 



Smitt described and listed this species from Florida at 30 to 68 

 fathoms; Canu and Bassler recorded it from the Gulf of Mexico and the 

 Straits of Florida. Osburn (1940) did not find it at Porto Rico, but 

 Hastings (1930: 733) noted its presence at Gorgona, Colombia, in the 

 Pacific Ocean. 



Dw^ri^w/fora.— Stations A42-39, At503, At504, At525, At526, 

 At527, At528, and At529. These stations place the locations at Cape la 

 Vela, Colombia; Aruba, Margarita and Tortuga Islands, and the Gulf of 

 Venezuela at 10 to 71 fms. 



