NO. 5 OSBURN : BRYOZOA 27 



on the basis of the presence of small sub-oral pores, but there is so much 

 variation that this character is not diagnostic. In Waters' excellent dis- 

 cussion (1923:556), while keeping innominata separate, he states that 

 "a sharp dividing line could not be found." Canu and Bassler ( 1928 : 73) 

 record them separately but state that "it is really impossible to distinguish 

 them specifically." Harmer (1926: 475) merges innominata with radiata 

 and Marcus (1937:73) does the same. Osburn listed them separately, 

 though questioning the distinctness. 



Apparently there is great variation in all of the essential characters, 

 so much so that it would be possible to set up numerous varieties on the 

 greater development of some particular character. The colonies in the 

 present collection are much like Smitt's figures of innomiata (plate 5, figs. 

 109, 110). 



Distribution. — Stations A18-39, At505, and At526. These stations 

 place the locations at San Nicolaas Bay, Aruba Island and Tortuga 

 Island at 21 to 24 fms. 



Genus MEMBRANIPORELLA Smitt 1873 

 Membraniporella petasus Canu and Bassler, 1928 



Canu and Bassler 1928: 36. 



This species resembles M. aragoi (Audouin) in the arrangement of 

 the frontal costules, though the costae appear to branch more frequently 

 than in that species. Younger specimens show usually four tips to each 

 costule; these meet at the midline and fuse leaving large lacunae. In 

 older specimens the costules become broader and the central portion of 

 the front becomes nearly closed. There is a strong suboral bar formed 

 by the fusion of the first pair of costules, a pair of short lateral spines 

 and a similar pair of terminal ones which, in fertile zooecia, unite across 

 the front of the ovicell. 



Distribution. — Stations A32-39, At505, and At512. These stations 

 place the locations at Coche, Aruba, and Cubagua Islands at 2 to 23 fms. 



ASCOPHORA 



Species with a calcified frontal and a compensation sac which permits 

 the inflow and outflow of water when the tentacles are protruded or 

 withdrawn. 



