ART. 13 



BKYOZOAN FAUNA CANU AND BASSLER 



57 



It lives rather frequently on floating algse, so that the bathymetric 

 indications which it can furnish are only relative. 

 Occurrence. — Galapagos Islands, D. 2813. 

 Cat. No. 8531, U.S.N.M. 



DEFRANCIA STELLATA Reuss. 1847 



Plate 14, Figures 7-12 



1847. Defrancia Stella ta Reuss, Die fossilen poljrparien des Wiener Tertiarbeck- 

 ens, Haidinger's naturwissenschaftliche Abhaudlungen, vol. 2, p. 37, pi. 

 6, fig. 2. 



1877. Defrancia stellata Manzoni, I Briozoi fossili del Miocene d'Austria ed 

 Ungheria, II parte, Denkschriften der math, natnr. Classe der k. Aka- 

 demie der Wisseuschaften, vol. 33, p. 16, pi. 16, fig. 63. 



/Structure. — It is quite remarkable to rediscover in the recent seas 

 this European fossil. We have been able to compare the Galapagos 

 specimens with different fossil specimens from the Canu collection, 

 and the identity of the micrometric measurements is as exact as 

 possible. 



In order to show the exactness of our determination we reproduce 

 at the same magnification fossil specimens. The only appreciable 

 difference is in the separation of the fascicles, which appears to be 

 slightly larger on the recent specimens. 



The specimen from the Lower Miocene of El Amran, Algeria, 

 shows manifest traces of the basal lamella around each subcolony. 

 The orifice of the tubes is a little smaller (0.06 mm.). The specimens 

 found in the Friren collection are simply marked " Helvetian " ; the 

 exact bed is unknown. The fascicles are a little narrower, measur- 

 ing 0.16 mm. 



The micrometric measurements of the specimen from the Sahelian 

 of Oran are exactly those shown in specimens from Galapagos. 



The entire absence of the solid substratum indicates a special 

 adaptation to floating life. Indeed most of the Galapagos specimens 

 are attached to floating cellepores. The following table gives a 

 summary of the micrometric measurements : 



