FOSSIL BRYOZOA FROM THE WEST INDIES. 97 



Genus BRACEBRIDGIA MacGillivray, 1886. 



Bracebridgia deformis, new species. 



(Plate 3, Figures 11 to 16.) 



The following is a description of this species: 



The zoarium is free, bilamellar, compressed, bifurcated. The zooecia are 

 distinct, elongate, separated by a deep furrow, claviform or elliptical; the 

 peristomice is oval or elliptical; an oblique avicularium is buried in the peris- 

 tomie; the apertura (visible only from the interior) is semilunar; the frontal 

 is surrounded by areolar, parietal pores, and on the old zocecia it bears a large 

 pore which does not perforate the wall. 



Measurements. — Peristomice: hpie=0.15 mm., lpie=Q.12 mm.; zocecium: 

 1,2=0.45 to 0.60 mm., lz=0.25 to 0.30 mm. 



Affinities. — This species has the exterior aspect of an Adeonellopsis. 

 The large frontal pore, however, is not a perforated area; it is invisible 

 in the interior, and its nature is unknown. The few specimens which 

 we have studied were, it is true, rather poorly preserved. 



The peristomial avicularium is rarely visible at the exterior; it is, 

 on the contrary, quite constant in the interior. This interior is that 

 of Bracebridgia; it is, therefore, indeed in this genus that it must be 

 classified, but it is a deformed Bracebridgia. 



The presence of a large frontal pore clearly characterizes this species, 

 and it clearly differentiates it from the other known species of the same 

 genus. 



Occurrence. — Lower Miocene (Bowden marl), Bowden, Jamaica 

 (rare). 



Family CELLEPORIDjE Busk, 1852. 



Genus HOLOPORELLA Waters, 1909. 



Holoporella albirostris Smitt, 1873. 



(Plate 1, Figure 19; Plate 7, Figures 9 to 14.) 



Discopora albirostris Smitt, Floridan Bryozoa, pt. II, Kongl. Svenaka. Vetenskaps-Akade- 

 miens Handlingar, XI, No. 4, p. 70, plate 12, figs. 233 to 239, 1873. 



Cellepora albirostris Jelly, A Synonymic Catalogue of the Recent Maiine Bryozoa, p. 45, 

 1889. (See for complete bibliography.) 



Holoporella albirostris Osburn, Bryozoa of Tortugas Islands, Carnegie Inst. Wash. Pub. No. 

 182, p. 215, 1914. 



Of the two specimens of this species which have been collected at 

 Panama and at Anguilla one corresponds to Smitt's figure 237 and the 

 other to figure 238. 



This species is one of the more common among the American fossils. 

 The Recent specimens are quite variable in aspect; the polymorphism 

 of the fossils is also quite remarkable on account of alterations. 



The avicularian beak is not as complete and well-developed as on the 

 immersed zocecia. It is quite often absent on the superficial zocecia. 



The interzocecial avicularium is spatulate; its distribution on the 

 zoaria is very irregular. 



The frontal is an olocyst bordered with areolar pores. 



