ART. 14 FOSSIL AND RECENT BEYOZOA CANU AND BASSLER 77 



HIPPOTHOA DIVARICATA Lamouroux, 1821 



Plate 28, Figure 7 



1918. Hippothoa divaricata Waters, Some collections of the Littoral Marine 

 Fauna of the Cape Verde Islands. Journal Linnean Society, Zool- 

 ogy, vol. 34, p. 20 (Synonymy). 



This cosmopolitan species has been noted at only one locality in 

 our Gulf of Mexico dredgings. Miss Jelly's catalogue and Water's 

 work cited above give its complete bibliography. 



Occurrence. — Albatross Station D. 2650, Bahama Islands; 23° 34' 

 30'' N.; 76° 34' 00" W.; 369 fms. 



Plesiotype.— Cat. No. 7523, U.S.N.M. 



Genus TRYPOSTEGA Levinsen, 1909 



TRYPOSTEGA VENUSTA Norman, 1864 



Plate 8, Figures 5, 6; text Figure lie 



1920. Trypostega venusta Canu and Bassler, North American Early Ter- 

 tiary Bryozoa. Bull. 106, U. S. National Museum, p. 330, pi. 85, fig. 

 15, 16. (Bibliography and geographic distribution.) 



Measurements. — Zooecia (distant from border)], „ * 



U2 = 0.26 mm. 



. ^ f^a = 0.10 mm. 

 Aperture , „ _ _ 

 ^ Ua = 0.06 mm. 



,, . , . [Z2 = 0.50-0.60 mm. 



Marginal zooeciai, „ „„ 



*^ [fe = 0.30 mm. 



. ^ iha = 0.10 mm. 

 Apertures , „ ^ _ 

 ^ lm = 0.06 mm. 



Variations. — In our bibliography of 1920 we omitted the variety 

 inornata Smitt, 1872 (not Gabb and Horn). We are now convinced 

 that this is indeed the same species in spite of the difference in size ; 

 in fact, the species is quite variable in its micrometric dimensions, 

 the marginal zooecia of the large colonies being much larger than the 

 others. The operculum presents the same variations; it closes the 

 ovicell. 



Biology. — The specimens encrust bryozoa {Steganoporella, Stylo- 

 poma), shells, corals (Oculina), hydroids, and nullipores; they prefer 

 smooth surfaces. They are light colored, but the operculum is 

 slightly yellow. Our specimens were in reproduction and fixation 

 from January to March; it is probable that they reproduce through- 

 out the year. 



This species is indifferent to bathymetric variations, but it prefers 

 depths from 10 to 100 meters. It has been observed in the Atlantic 

 as far as the fiftieth parallel. 



