^RT. 14 FOSSIL AISTD SECEl^T BRYOZOA CANU AND BASSLER 31 



Structure. — Lang, 1914, considered the orifices placed on the caudal 

 portion of the zooecia as avicularia. We have seen no mandibles on 

 our living specimens, and the orifices observed are indeed the aper- 

 tures of successive zooeciules forming the caudal portion of the zo- 

 oecia. The zooeciules form thus true stolons of variable length which 

 are not necessarily terminated by a zooecium. Our Figure 1 shows 

 this phenomenon as perfect evidence. In their form these zooeciules 

 are related to those of Trypostega; however, the latter are always 

 isolated and in direct connection with the proximal zooecium. It is 

 probable that these zooeciules are deprived of polypides. They differ 

 from true stolons of Ctenostomata in the presence of an orifice. 



The figure of Lang seems to indicate that the ovicell is closed by a 

 special operculum as in Callopora, but his species is a fossil one, and 

 we know how difficult it is to determine by the examination of the 

 skeleton alone the relation of the operculum and the ovicell. In our 

 specimens without any doubt the operculum closes the ovicell. In 

 spite of this divergence, we do not believe we ought to create a new 

 genus for the stoloniferous Membranipores, for it is preferable to 

 attribute to the fossils the characters of the recent species. 



Biology. — Our specimens from locality D. 2167 were alive when 

 dredged. They were in reproduction May 1, 1884. 



Occurrence. — Albatross Station D. 2167, off Habana, Cuba; 23° 10' 

 40'' N.; 82° 20' 30" W.; 201 fms.; coral. 

 Albatross Station D. 2319, north of Cuba; 23° 10' 

 37" N.; 82° 20' 06" W.; 143 fms.; gray coral. 



Cotypes.—Csit. Nos. 7543, 7544, U.S.N.M. 



Genus CALLOPORA Gray, 1848 



CALLOPORA TENUIROSTRIS Hincks, 1880 



Plate 3, Figure 4 



1918. Membranipora tenuirostris Waters, Bryozoa of the Cape Verde 

 Islands. Linnean Society's Journal, Zoology, vol. 34, p. 9. (Bibli- 

 ography and geographic distribution.) 



1920. Callopora tenuirostris Canu and Bassler, North American Early Ter- 

 tiary Bryozoa. Bull. 106, U. S. National Museum, p. 114, pi. 29, 

 fig. 10, 11. (Bibliography.) 



,, ^ /-^ • [i^o = 0.40 mm. 



Measurements. — Opesiai, „ „ . 



^ Uo = 0.24 mm. 



. fZ2 = 0.40-0.54 mm. 

 Zooeciai, „ „„ 



Us = 0.36 mm. 



Variations. — The micrometric measurements are very variable; 

 specimens from Oran measure 0.50 mm. by 0.44 mm. Waters's fig- 

 ure of 1898 shows 0.40 mm. by 0.28 mm., and fossils from the Jack- 

 sonian measure 0.40-0.45 mm. by 0.20-0.25 mm. 



