NO. 5 OSBURN : BRYOZOA 13 



Family AldeHnidae Canu and Bassler 



Genus ALDERINA Norman 1903 



Alderina irregularis (Smitt), 1873 



Smitt 1873:8 (Membranipora). Osburn 1914:194 (Membranipora) ; 



1940: 363. Canu and Bassler 1928: 28. 



Recorded by Smitt from Florida, by Osburn from the Tortugas 

 Islands and by Canu and Bassler from the Gulf of Mexico, Straits of 

 Florida and north of Cuba. Hastings (1930:708) has also listed it 

 from Gorgona, Colombia, on the Pacific side. 



Distribution. — Stations A32-39, At505, and At526. These stations 

 place the locations at Coche and Tortuga Islands at 19 to 41 fms, 

 several small colonies. 



Genus GRASSIMARGINATELLA Canu 1909 

 Crassimarginatella leucocypha Marcus, 1937 

 Marcus 1937:46. Osburn 1940:351 (Conopeum reticulum, in partj. 



Apparently there has been much confusion about the identification of 

 Membranipora reticulum L. and Marcus has helped to solve a part of 

 it by separating the form with interzooecial avicularia into a new species 

 of Crassimarginatella. The writer must confess to finding many diffi- 

 culties with the species which have "triangular interspaces" at the base 

 of the zooecia. In his Porto Rico paper (1940: 350) Osburn wrote that 

 the triangular spaces "are developed upon the gymnocyst and are there- 

 fore merely interopesial. In the same colony there may be other, usually 

 more rounded or ovate, cavities which go right down to the dorsal side 

 of the zooecia and which are certainly interzooecial." As no avicularia 

 could be found on these interzooecial cavities, their nature was not under- 

 stood. Marcus found small rounded avicularia, and these occasionally 

 occur in our present material. Now the writer thinks there can be no 

 doubt that the specimens from the Gulf of Mexico and West Indies with 

 triangular spaces (or tubercles as they sometimes are called) and inter- 

 zooecial avicularia belong to Marcus' species. 



Distribution.— ^tztxon'i A13-39, A25-39, A27-39, A30-39, A32-39, 

 A42-39, A87-46, At503, At505, At512, and At528. These stations place 

 the locations at Marco Island, Florida; Cape la Vela, Colombia; 

 Cubagua, Coche, Aruba, and Margarita Islands and the Gulf of Vene- 

 zuela at shore to 23 fms. 



