iiRT. 13 BRYOZOAN FAUNA CANU AND BASSLER 33 



CREPDroACANTHA POISSONII Savigny-Andouin, 1826 



Plate 5, Figure 5 



3928. Crepidacantha poissonii Canu and Basslehi, Bryozoaires des lies Hawaii, 

 Bull, de la Societe des Sciences de Seine et Oise, fasc. 7, p. 37, pi. 8, fig. 7. 



Measv/rements. — 



ry^^=0.10mm. . fZs = 0.54-0.60 mm. 



ry^^=0.10mm. fZs = 0.54-0.6 



Stimcture. — This species is very vigorous in the Galapagos Islands, 

 and its dimensions are somewhat larger than those of a specimen 

 from the Hawaiian Islands, of which we give a photograph. The 

 characters are quite the same as those of specimens from Madeira 

 and Panama. The ovicell is decorated -with a distal border and the 

 two vibracula are placed below the aperture. The latter are not 

 always arranged symmetrically (as in Panama), but they are some- 

 what more removed from each other as at Madeira. 



The operculum has the ordinary form of the opercula of the 

 species dredged at the Philippine Islands, with two lateral bands 

 curved for muscular attachments. 



A-fjinities. — Hincks, 1885, wrote that at Tahiti and New Zealand 

 " two forms occur — in one the vibracula are situated below the 

 orifice and are placed horizontally (=typica) ; in the other they are 

 vertical and placed at the side of the orifice near the top of it and 

 close to the margin (=new species)." He cites also a common fossil 

 in New Zealand a variety of Crepidacantha poissonii with " orifice 

 very small and the vibracula are placed in good way down the cell 

 with a prominent central umbo between them." This is a distinct 

 species which we have called Crepidacantha parvipora. 



Waters, 1887, also cites from New Zealand Lepralia poissonii^ of 

 which he gives the operculum. This is not the same as our identifica- 

 tion of the species because he has selected the second form with 

 lateral vibracula, which Hincks mentions in 1885. We have called 

 this species C. zelanica, although we can not give all the characters, 

 for we know only the operculum and the place of the avicularia. It 

 is perhaps Crepidacantha setigera MacGillivray, 1882 (not Smitt, 

 1873) ; but we have no illustration permitting as to make this 

 synonymy. Moreover MacGillivray's species, differing notably from 

 that of Smitt, has caused us to change his specific name and to call 

 it Crepidaxxmitha setifera. Hincks, 1885, in writing that the place 

 of the vibracula was of no importance appears to have caused all the 

 confusion. 



Finally Waters, 1889, figures a variety of Crepidacantha poissonii 

 from Australia with an ovicell " immersed " ; that is to say, endo- 



61589—29 3 



