NEW ANTILLEAN MOLLUSKS — EEHDER 189 



The type, U.S.N.M. No. 517057, measures : Height, 5.9 mm. ; length, 

 (5 mm., breadth, 4.2 mm. It was collected by Ted Bayer in Lake 

 Worth, Fla. 



Genus ERVILIA Turton, 1822 



ERVILIA ROSTRATULA, new species 

 Plate 19, Figures 1-2 



Shell small, stout, subtrigonal, rather inflated, white or yellowish, 

 posterior end slightly rostrate, sculpture consisting of strong con- 

 centric riblets, crossed posteriorly by fine radial lines. Hinge typi- 

 cally erviliid. 



The type, U.S.N.M. No. 517059, was collected with several others 

 by Ted Bayer in Lake Worth. It measures : Length, 4.5 mm. ; height, 

 3.3 mm., breadth, 2.3 mm. 



This species is closest to the Bermudian subcancellata E. A. Smith, 

 differing in being more inflated, more trigonal, and posteriorly ros- 

 trate and having the radial sculpture restricted more to the posterior 

 end. 



Genus ASTHENOTHAERUS Carpenter, 18G4 



ASTHENOTHAERUS BALESI, new species 

 Plate 19, Figures 13-14 



Shell ovate, thin, grayish white, anterior end rounded, posterior 

 end slightly narrower and truncated, with a ridge running from the 

 median, opisthogyrate umbo to the posteroventral angle. The early 

 portion of the shell is sharply biangulate and evenly concentrically 

 ribbed; in the later portion the concentric ridges become irregular 

 folds, giving the shell a slightly rugose appearance. An elongate 

 calcareous lithodesma, broadly angled in the middle, lies under the 

 umbones in a spongy cartilage. Pallial sinus moderately deep. 



The type, U.S.N.M. No. 536052, measures : Length, 10.5 mm., height, 

 7.6 mm. It was found by Dr. B. R. Bales on Missouri Key, Fla. 



This species differs from the only other known West Atlantic 

 species, A. hemphffli Dall, in having a more elongate-ovate shape 

 and more central umbones. 



Genus POROMYA Forbes, 1844 



POROMYA ROSTRATA, new species 



Plate 19, Figuiu s ! L-12 



Shell small, inflated, slightly inequivalve, right valve slightly 

 larger and deeper with a more prominent umbo; broadly and ir- 

 regularly ovate in shape, posteriorly rostrate, the left valve being 

 more rostrate than the right; umbones central. External surface 



