98 PROCEEDIISTGS OF THE NATIONAL MUSEUM vol.72 



Affinities. — The determination of this species is not always easy, 

 for it may be confused with two other species of the same general 

 aspect and with analogous dimensions. It differs from Stylopoma 

 spongites Pallas, 1766, in the nature of its ovicell which does not hide 

 the aperture, and in its much larger apertural rimule. It differs from 

 Scliizopodrella pungens, new species, in the absence of an umbo on the 

 frontal and in its transverse and nonelongated aperture. It is not 

 Escharina isabelleana D'Orbigny, 1839, in which the avicularium is 

 placed at the side of the anter and in which the affinities according 

 to Waters, 1906, are rather with Scliizopodrella unicornis Johnston, 

 1847. 



Biology. — Our colonies were bluish; this is perhaps what Smitt 

 wished to express in writing that his were of purplish blue tint. They 

 were ovicelled, but as we have not seen the ancestrula it is probable 

 that this was not the month of the escape of the larva and of the 

 fixation. 



The avicularia have generally a very salient beak oriented obliquely 

 toward the superior part of the zooecia. Their presence is constant. 

 They are often adjacent to the poster, never the anter. We think 

 that they are oral and that their presence is to supply some internal 

 function of which we are unfortunately ignorant. In the other species 

 of this genus the avicularia are frequently two in number, symmetri- 

 cally placed on each side of the aperture; it would be convenient then 

 to place Schizopodrella pungens and S. isabelleana in a special section. 



The colonies fixed on algae belong to the category of floating bryo- 

 zoa. They have not necessarily lived at the place where they were 

 dredged and they do not therefore furnish exact bathymetric data. 



Occurrence. — St. Thomas, Virgin Islands, West Indies; Florida, 27 

 meters (?) (Smitt). 

 Pliocene : Minnitimmi Creek, Bocas Island, Almirante 

 Bay, northwest Panama. 



Plesiotypes. —C&t. No. 7584, U.S.N.M. 



Genus GEMELLIPORA Smitt, 1873 (part) 



GEMELILPOKA GLABRA Smitt, 1873 



Plate 12, Figures 1-7; text Figure 16 



1885. Gemellipora glabra Busk, Br5'^ozoa of the Challenger. Report Scientific 

 Results Voyage Challenger, vol. 10, p. 176, pi. 25, fig. 3. 



1873. Gemellipora glabra Smitt, Fioridan Bryozoa. Kongl. Svenska Veten - 

 skaps Akademiens, Handlingar, vol. 11, p. 37, pi. 11, figs. 207-210 



Tir ^ \ J. ilia = 0.18 mm. 



Measurements. — Aperturei, ^ ,^ 



Ua = 0.12 mm. 



ry . [is = 1.1 mm. 

 Zooecia-^ 7 



U2 = 0.5 mm. 



