120 PEOGEEDINGS OF THE NATIONAL MUSEUM vol.72 



The peristomice is much larger than the aperture; it opens the 

 locella in which the operculm operates and which serves as a passage 

 for the larvae. 



Occurrence. — Cedar Keys, Fla. 



Holotype.— Cat. No. 7610, U.S.N.M. 



Genus RHAMPHOSTOMELLA Lorens, 1886 



RHAMPHOSTOMELLA MAGNIROSTRIS, new species 



Plate 19, Figures 5-7; text Figure 22 e. / 



Description. — The zoarium is free, uni, or bi lamellar; the fronds 

 are very irregular. The zooecia are little distinct, separated by a 

 furrow, elongated, elliptical; the frontal is convex, bordered with 

 areolar pores and ornamented with irregular costules. The aperture 

 is large, elliptical, transverse, or suborbicular; the proximal border 

 bears a wide lyrule placed eccentrically; the avicularian umbo is 

 salient, arranged obliquely and partially covering the aperture. The 

 ovicell is large, globular, formed of two calcareous lamellae and orna- 

 mented with punctations. 



,, J A i \Jia==0.25 mm. 



Measurements. — Aperture, ^ ^„ 



^ Ua = 0.22 mm. 



fLz = 0.75 mm. 



ZooeciaL _ .. 



lte = 0.40 mm. 



Variations. — The much calcified zooecia present fantastic forms; 

 strong salient threads unite the ovicells, the frontal becomes concave, 

 the IjT-rule disappears, the avicularian umbo is lacking, and it is re- 

 placed sporadically by an enormous avicularium with a large triangu- 

 lar mandible. 



Affinities. — The genus BJiampliostomella is very common in the 

 recent northern seas. Its presence in the Priabonian of the Vicentin, 

 Italy, in the Jacksonian of the two Carolinas and of Georgia and in 

 the Vicksburgian of Alabama proves that it can inhabit the warmer 

 waters and approach the equatorial zone. Its presence in Florida 

 confirms this observation deduced from paleontology. 



In the form of its elliptical operculum this new species approaches 

 Bhamphostomella costata Lorenz, 1886, but differs from it in its free 

 zoarium and its smaller and more irregular costules. It approaches 

 more Rham].)kostomella hilaminata Hincks, 1877, dredged more to the 

 north in the American waters but differs from it in its large lyrule 

 and in the presence of its large sporadic avicularia. The operculum 

 is very thick, elliptical, little resembling the form of the aperture. 

 Its margins are thin. 



Occurrence. — Cedar Keys, Fla. 



Cotypes.— Cat. No. 7579, U.S.N.M. 



