108 PROCEEDINGS OF THE NATION"AL MUSEUM vol.72 



Occurrence. — Albatross Station D. 2362, east of Yucatan; 22° 08' 

 30" N.; 86° 53' 30" W.; 25 fms.; coral sand. 

 Florida, 97 meters (Smith). 



Pliocene: Minnitimmi Creek, Bogus Island, Almirante 

 Bay, Panama. 

 GeograpMc distribution. — Northern Atlantic: Europe from the 

 mouth of the Loire to Spitsberg. America; Florida and Greenland. 

 Mediterranean. 



Plesiotype.— Cat. No. 7521, U.S.N.M. 



Genus HIPPOMENELLA Canu Bassler, 1917 



HIPPOMENELLA RUBRA, new species 



Plate 10, Figure 7; text Figure 19c 



Description. — The zoarium is unilamellar and creeps over algae » 

 it is a beautiful glistening red. The zooecia are distinct, separated 

 by a deep fnrrow, elongated, ovoid, swollen; the frontal is convex, 

 ornamented by a double range of areolar pores and by small gran- 

 ules. The aperture is large, elongated, elUptical; the peristome is 

 salient and formed by the tremocyst; it bears six to eight large hol- 

 low spines; it is enlarged and expanded in its proximal portion- 

 The ovicell is large, globular, buried in the distal zooecium, closed 

 by the operculum; it is bordered with areolar pores ornamented with 

 costules converging toward a proximal tuberosity. The avicularia 

 are implanted in the vicinity of the peristome; they are long, thin, 

 triangular, tapering; their beak is directed exteriorily and turned 

 toward the base. 



,, . A .. \ha = 0.15-0. 18 mm. 



Measurements. — Apertureu _ ,„ _.^ 



^ ife = 0.13-0.15 mm. 



r, . [1:0 = 0.70-0.75 mm. 

 Zooeciau _ .„ 



Us = 0.60 mm. 



Affinities. — The ancestrula is very small, its frontal is very short. 

 The ancestrular zooecia are smaller than the marginal zooecia and 

 are deprived of avicularia. The avicularia are inconstant and often 

 absent; we consider them as zoarial. 



HippotJioa mucronata Smitt, 1873, is a species very close, perhaps 

 identical, having the same frontal, same ovicell, the same spines, 

 and the same color. Our species differs from it only in the presence 

 of the avicularia and in the tuberosity of the ovicell placed lower 

 and not in the middle. 



This species differs from Lepralia mucronellijorjnis Waters, 1899, 

 from Madeira in its smaller dimensions, a larger aperture, and two 

 more spines on the peristome. 



The discovery of this species in the Gulf of Mexico is important, 

 for it permits the recognition of the true characters of the genus 



