ART. 14 FOSSIL AND KBCEN'T BEYOZOA — GAFU AKD BASSLER 103 



GEMELLIPORIDEA MAGNIPOROSA Canu and Bassler, 1923 



Plate 11, Figures 5-11, text Figure 17 d, e 



1923. Schizoporella magniporosa Canu and Bassler, North American Later 

 Tertiary and Quaternary Bryozoa. Bull. 125, U. S. National 

 Museum, p. 95, pi. 45, figs. 1, 2. 



-,, J A i f^a = 0.16 mm. 



Measurements. — Aperture-i, _ n 19 



„ . jL2 = 0.60 mm. 



\lz = 0.4:0 mm. (variable). 

 Structure. — We discovered this species in the Pleistocene of Pan- 

 ama, but on the fossil specimens we were unable to discern the true 

 nature of the aperture; the operculum is that of a Gemellipora but 

 somewhat attenuated and less oval; the ornament on it is variable. 

 The zooecia are not always regularly oriented. Inverse zooecia 

 are formed sporadically and completely disarrange the regularity of 

 the budding. We have observed this phenomenon in many genera 

 but we are ignorant of its cause. For species with celleporine struc- 

 ture Smitt, 1867, created the genus Herentia, but this name has not 

 been admitted into nomenclature because of great diversity of the 

 species. 



The zooecia are generally separated by a salient thread. The two 

 small oral avicularia are triangular, with pointed and very salient 

 beak in front of the zooecial plane; they are very difficult to illus- 

 trate. They are constant, but sometimes one of them is lacking. 

 The ovicell appears on the normally oriented zooecia; it is globular, 

 closed by the operculum and covered by large tremopores Hke the 

 frontal. 



The dimensions are quite variable especially in width. The deter- 

 mination of isolated specimens is quite difficult. 



Biology. — The colonies encrust bryozoa, shells, or grains of sand 

 joined together. Many lamellae are often superposed. The for- 

 mation of inversed zooecia is, morever, absolutely connected with 

 the plurUamellar phase, for we have observed it in other species of 

 very different genera. The architecture of the bryozoa is so compU- 

 cated that it often escaped our comprehension. 



Our specimens were in reproduction from January to April. 

 Occurrence. — Albatross Station D. 2157, Gulf of Mexico, off 

 Habana; 23° 10' 04'' N.; 82° 21' 07" W.; 29 fms. 

 Albatross Station D. 2169, off Habana, Cuba; 23° 10' 



28" N.; 82° 20' 27" W.; 78 fms.; coral. 

 Albatross Station D. 2362, east of Yucatan; 22° 08' 



30" N.; 86° 53° 30" W.; 25 fms.; coral sand. 

 Pleistocene of Panama (Canu and Bassler). 

 Plesioty pes. —C&t. Nos. 7503, 7504, U.S.N.M. 



