THE MOUNT DESERT EEGION 299 



The species is common in the region about Mt. Desert 

 Island, at all depths down to 100 meters, on stones and shells, 

 and was noted at twenty-three different stations. In my col- 

 lection the species is otherwise represented by specimens from 

 the Gulf of St. Lawrence (J. F. Whiteaves, 1873), from Crab 

 Ledge off Cape Cod, from LTnited States Fisheries Station 68, 

 and""off the Isles of Shoals (Str. Bache, 1874). The last 

 specimen bears the label ^Diastopora hyaJina (Flem.) Smitt,' 

 presumably in Verrill's writing. 



This species is here placed in the genus Oncousoecia Canu, 

 1918. ''The ovicell is a dilation of the entire visible part of 

 the tube. The ooeciostome is not turned toward the base." 

 While the conception of the genus is good, Canu was most un- 

 fortunate in his selection of the genotype ^Tuhulipora lobulata 

 Hincks." In his description of the genus, Canu had in mind 

 the ooecium shown in Hincks figure 5 (British Marine Poly- 

 zoa„ pi. 61), which he reproduces. Now Doctor Hastings 

 writes that ''Hincks expressly states that he based his de- 

 scription on material from the Isle of Man and drew figure 4 

 of plate 61 from that locality, but he drew figure 5 from a 

 specimen from Shetland in the Norman Collection, which 

 proves on examination to be specifically distinct. In my 

 opinion it is to be identified with Alecfo dUatans Thomson 

 (Johnston, 1847, British Zoophytes, ed. 2, p. 281)." A. dila- 

 fans Thomson should therefore stand as the genotype of 

 Oncousoecia Canu. 



Doctor Hastings' study of the genotype specimen necessi- 

 tates a short addition to Canu's description. "The fertile 

 zooecium originates in its normal place in the series of zooecia 

 and the proximal portion of the part visible is indisting-uish- 

 able in shape, position and pores from an ordinary zooecium. 

 This part is short and the greater part of the visible portion 

 is dilated and closely punctate, with a rather flat frontal 

 surface. The fertile zooecium is a good deal longer than 

 an ordinary zooecium and thus extends distally beyond the 

 point at which an ordinary zooecium would have opened. The 

 ooeciostome is terminal. It is a circular tube directed up- 



