46 PEOCEEDINGS OF THE NATIONAL MUSEUM VOL. 76 



more rare. The species has apparently degenerated in the Pacific 

 since the formation of the Isthmus of Panama. 



OcGurrence. — Galapagos Islands, D. 2813. 



Cat. No. 8521, U.S.N.M. 



Order CYCLOSTOMATA Busk 



Family DIASTOPORIDAE Gregory, 1899 



Forma PROBOSCINA Audouin, 1826 



PROBOSCINA LAMELLIFERA, new species 



Plate 11, Figures 1, 2 



Description. — The zoarium incrusts shells and is formed of sinuous 

 branches joined together by a smooth calcareous lamella. The tubes 

 are indistinct, short, serrated, and terminated by a long peristomie 

 perpendicular to the zoarial plane. 



Measurements. — Diameter or orifice, 0.12 mm. ; diameter of peris- 

 tome, 0.16-0.18 mm. ; internal separation of tubes, 0.20-0.30 mm. ; 

 width of branches, 1.5 mm. 



Acuities. — This arrangement of the branches on a calcareous 

 lamella, cellular because of decortication, is quite special and very 

 characteristic. It has been observed only on the fossils, notably on 

 Idvionea hagenawi Sharpe, 1854, from the English Cenomanian, and 

 on Tuhulipora hidupUcata Waters, 1887, from the Miocene of New 

 Zealand. It is interesting to rediscover in the recent seas a feature 

 observed in the ancient seas, permitting an explanation of the struc- 

 ture. Unfortunately the number of our specimens was too small for 

 a detailed study by thin sections. 



It is necessary to note the special arrangement of the peristomes; 

 they are oriented not longitudinally as in true Prohoscina but ob- 

 liquely toward the zoarial margins as in Idmonea. 



Occurrence. — Galapagos Islands, D. 2813. 



H olotype.— Csit. No. 8522, U.S.N.M. 



Family ONCOUSOECIIDAE Canu, 1918 

 Genus ONCOUSOECIA Canu, 1918 



ONCOUSOECIA (PROBOSCINA) MAJOR Johnston, 1847 



1884. Stomatopora major Hincks, Polyzoa of Queen Charlotte Islands, Annals 

 and Magazine of Natural History, ser. 5, vol. 10, p. 204 (sep. 33). 



1889. Stomatopora major Jeixy, A synonymic Catalogue of Marine Bryozoa, 

 p. 257 (bibliography). 



1900. Tuhulipora (Stomatopora) major Neviani, Bryozoi neogenici della Cala- 

 brie, Paleontographica italica, vol. 6, p. 235 (sep. 121) (local bibliog- 

 raphy). 



