18 PEOCEEDINGS OP THE NATIONAL MUSEUM vor,. 72 



This species corresponds rigorously to the genus Quadricellaria 

 D'Orbigny, 1851. All the Cretaceous species, except one, described 

 by this author have this structure. This discovery shows again 

 that the study of the equatorial bryozoa is indispensable to' the 

 paleontologist. 



Biology. — The ectocyst is not pigmented; its natural tint is light 

 colored. We have observed some zooecia closed by a calcareous 

 lamella perforated at the center. The collection of numerous speci- 

 mens is necessary to study the complete structure of this important 

 species. 



Occurrence. — Albatross Station D. 2136, Caribbean Sea; 17° 43' 

 40" N.; 75° 38' 25" W.; 52 fms.; coral, broken shells. 



Cotypes.-—C8it. No. 7574, U.S.N.M. 



Family ELECTRINIDAE D'Orbigny, 1851 



Genus NITSCHEINA Canu, 1900 



Harmer ("Siboga," 1926) adopts Nichtina (Nitsclieina) Canu, 1900, 

 for the M. membranacea group in place of Membranipora which he 

 retains for unplaced members of the Membraniporae. Although we 

 have previously employed Membranipora as a valid genus, we now 

 follow this eminent authority. 



NITSCHEINA MEMBRANACEA Linnaeus, 1766 



Plate 1, Figure 4 



1914. Membranipora membranacea Osbukn, Bryozoa from the Tortugas 

 Islands, Florida. Publication Carnegie Institution, Washington. 

 No. 182, p. 193 (American bibliography) . 



This is an almost universal species and has been noted in the Tem- 

 perate Zones of both hemispheres. Observed in California and in 

 Alaska by Miss Robertson and recorded by Osburn at the Tortugas, 

 It was unknown in South America until the Albatross dredged very 

 beautiful specimens off Chili. 



The species differs from NitscTi^eina {Membranipora) tuberculata Bosc, 

 1802 { = Membranipora teJiuelca D'Orbigny, 1839), in its small tubercles 

 which are vertical (not oblique) and never united together. 



Occurrence. — Albatross Station D. 2782, off Chili, South America; 

 51° 12' 00" S.; 74° 13' 30" W.; 258 fms.; blue mud. 



Plesiotype.— Cat. No. 7548, U.S.N.M. 



NITSCHEINA TUBERCULATA Bosc, 1802 



1914. Membranipora tehuelca Osburn, The Bryozoa of the Tortugas Islands, 

 Florida. Publication Carnegie Institution, Washington. No. 182, 

 p. 193. (American bibliography.) 



1921. Membranipora tehuelca Robertson, Bryozoa from the Bay of Bengal. 

 Records of the Indian Museum, vol. 22, p. 47. 



