24 Melvill, Descriptions of Marine Mollusca. 



DONAX APERITTUS, Sp. 110V. (PL J, f. 33). 



D. testa solidiuscula, compacta, Icevi, nitida, indistincte 

 lirata, latere antico prodncto, postico subtruncato, paullum 

 extenso, radiatim recti-corrugato, margine ventrali minute 

 serrato, umbonibns inconspicuis, planatis. 



Long. 8, lat. 15 mm. 



Hab. Karachi. 



A smooth shell, with the anterior side produced, some- 

 what truncate, though slightly extended also posteriorly, 

 the radiate corrugations being prominent ; the rest of 

 the surface almost smooth, the umbones inconspicuous ; 

 ventral margin minutely serrate. 



(cnrepiTTOs, simple.) 



Pectunculus maskatensis, sp. nov. (PL 7, f. 32). 



P. testa paullum compressa, cequilaterali, solidiuscula, 

 rotundata, dorsaliter recta, brunneo-rufo-alboque sparsa, um- 

 bonibus parvis sed conspicuis, radiatim fortiter costulata, costis 

 uniformibus, apud medium et infra sulculo divisis, utrdque 

 parte nodulis parvis decoratis, interstitiis spiraliter tenuissime 

 liratis, cardine dentibus octodecim in utrdque valvd instructo, 

 pidchre britnneo-tinctis, interiore albo-lacteo. 



Alt. 22, lat. 25, diam. 10 mm. 



Hab. Muscat (or Maskat), Arabia, 10 fathoms in sandy 

 mud. 



Allied to the well-known P. pectiniformis, Lam., but 

 the ribs, as seen by the above description, are of an 

 entirely different character, being smooth and undivided 

 by a sulculus in Lamarck's species. It ranks among the 

 more select of a genus famous for a highly-individualised 

 type of beauty. 



