MUSEUM OF COMPARATIVE ZOOLOGY. 225 



Lima hians Gmelin. 



Ostrea hians Giuel. S. N. 3333. 



Lima frayilis Montague, Test. Brit. Suppl., p. 62. 



Lima tenera Turton, Zool. Journ., V. p. 362, pi. xiii. fig. 2. 



Lima aperta Sowerby, Thes. Conch., I. p. 87, pi. xxii. figs. 26-29. 



One valve was obtained near Santa Cruz, at Station 127, in 38 fms. 



Lima albicoma, n. s. 



Shell small, short, waxen gray, very inequilateral ; sharply truncated above 

 and roundly produced below, anteriorly ; hinge-line short, cardinal area trian- 

 gular with a narrow long cartilage in a shallow sulcus overhung at the outer 

 end by the acutely pointed umbo ; anterior edges of the cardinal and truncated 

 areas strongly carinate ; between the carinae the truncature is concave with one 

 strong and two or three fine radiating threads parallel with and near to the 

 longer carina, the rest of this area striate with lines of growth ; the anterior 

 angle of the hinge margin hidden in the concavity, when the shell is viewed 

 from the side; the posterior angle is visible, but not prominent, though sharp ; 

 from this angle to the outer end of the anterior carina the base describes two 

 thirds of a circle ; exterior smooth, finely regularly grooved with very numer- 

 ous punctate grooves, at the basal margin about ten to the millimeter; the.se 

 grooves radiate primarily from two imaginary lines, one of which (somewhat 

 as in L. tenera and L. scabra) is median to the umbo and the base. The 

 other is nearly similarly situated with regard to the former, posteriorly, as 

 the margin of the truncature is, anteriorly ; hinge-line smooth. Max. alt. 

 8.00; max. Ion. 8.00; max. diam. 4.00; hinge-line 2.75 ; Ion. of truncature 

 6.00 mm. 



A valve of this interesting species was dredged at Barbados, in 100 fms. ; the 

 type was dredged by the Fish Commi-ssion steamer "Albatross" at Station 

 2322, near Havana, in 115 fms. 



The peculiarities of sculpture, ajjart from all the other characters, sufficiently 

 separate this from any other described species. 



Genus LIMATULA S. Wood. 



Limatula setifera, n. s. 



iLimattda ovata Dall, Bull. M. C. Z., IX. p. 118, 1881 (not of Wood or Jeffreys). 



Shell ovate, inflated, white, with about thirty-four radiating acute ribs, 

 strongest in the middle of tlie valve, with a fine sharp thread in the channel 

 between each pair of ribs ; both ribs and threads sharp, thin, and produced 

 into a series of sharp spines, which in perfect specimens are nearly as high as 



VOL. XII. — NO. 6. 15 



