NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 147 



ing of the frontal walls; but it does not really belong to this genus because it has no 

 lyrula nor oral avicularium and because the apertura is not semilunar. 



Occurrence. — Lower Miocene (Bowden horizon) : Cercado de Mao, Santo 

 Domingo (rare). 



Holotype.—Ca,t. No. 68647, U.S.N.M. 



SMITTINA PORIFERA Hlncks, 1884. 



Plate 3S, fig. 9. 



1884. Porella inarsupium forma porifera Hincks, Report on Polyzoa of Queen Charlotte Islands, 

 Annals Magazine Natural History, ser. 5, vol. 13, p. 50 (sep. 24), pi. 4, fig. 4. 



1887. Porella marsupium, var. porifera Waters, Tertiary Cheilostomatous Bryozoa from New Zea- 

 land, Quarterly Journal Geological Society London, vol. 42, p. G3. 



Description. — The zoarium is incrusting. The zooecia are distinct, swollen, 



separated by a deep furrow, very convex, perforated by some pores widely spaced. 



The frontal is a pleurocyst garnished laterallj' with six large areolar pores, of which 



the two superior ones are sometimes changed into avicularia. The apertiu-a is deep, 



hidden by the peristomie and by a small, salient, orbicular, oral avicularium. The 



peristome is thin and bears four small spines which are often replaced by a small 



distal orbicular avicularium (rarely two). There is a very small lynda hidden by 



the frontal avicularium. The ovicell is globidar, salient, smooth; it opens above 



the operculum by a very large opening. 



,, , A ^ f/ia = 0.12 mm. „ . fX2 = 0.45 mm. 



Measurements. — Apertura , „ , „ Zooecia , 



^ lta = 0.12mm. [<z=0.28mm. 



The avicularium chamber forms a frontal gibbosity perforated by four large 

 pores. The latter characterize the species, for they do not exist in Porella mar- 

 supium MacGLUivray. 



Occurrence. — Pleistocene : Santa Monica (Long Wharf Canyon) , California (rare) . 



Geological distribution. — Pliocene of New Zealand (Waters). 



Habitat. — Queen Charlotte Islands (Hincks). 



Plesiotype.—Ca.t. No. 68648, U.S.N.M. 



Genus PORELLA Gray, 1848. 

 (For description, see Bulletin 106, U. S. National Museum, p. 479.) 



PORELLA BELLA Busk, 1860. 



Plate 1, fig. 12. 



1860. Lepralia bella Busk, Zoophytologv, Quarterly Journal Microposropical Science, vol. 8, pi. 27, 



fig. 2, 3. 

 1873. Escharella landnborovi Smitt, Floridan Brj-ozoa, pt. 2, Kongl. Seven. Vet. Akad. Hand., vol. 



11, no. 4, p. 60, pi. 10, figs. 201, 202. 

 1880. Smittia bella Hincks, British Marine Polyzoa, p. 3.52, pi. 42, figs. 9, 10. 

 1919. Porella bella C.\Nu and B.\ssler, Geology and Paleontology of the West Indies, Brj'ozoa, 



Publications of the Carnegie Institution, no. 291, p. 93, pt. 1, fig. 15. 



We are not certain that Busk's species is identical with that of Smitt, as the 



former author represents it, but is evident that the characters of our Antigua fossil, 



although it is poorly preserved, are in harmony with Smitt's figures. Following 



are the measurements of this fossil. 



, ^ (?ia = 0.16mm. „ . fi2 = 0.90nim. 



Apertura , _ „„ Zooecia , . „. 



^ Ua = 0.20 mm. [t2 = 0.^0mm. 



