218 



LETTER XV. 



VULSELLA MALLEUS AVICULA PERN A CRENATULA 



PL AC UN A HARPAX PECTEN LIMA PEDUM PANDORA 



CORBULA ANOMIA CRANIA TEREBRATULA CALCEOLA 



HYALJEA ORBICULA LINGULA BALANUS TUBICINELLA.... 



CORONULA ANAT1FA. 



CXXXVIII. Vulsella. A free, longitudinal, nearly equivalved shell, 

 with a flattish callous hinge, without teeth, projecting alike on each 

 valve ; and a conical rounded pit for the ligament, terminating in a very 

 short bent beak. 



This genus is formed by Lamarck for the reception of Mya vulsella, 

 Linn. ; Vulsdla lingulata, Lam. Rumph. Mus. Tab. 46, Fig. A. It is 

 not, I believe, known fossil. 



CXXXIX. Malleus. A free shell, a little gaping near the beaks, 

 fixing itself by a byssus, and having its valves of the same size. The 

 hinge without a tooth, rather projecting, . and supplied with a pit for the 

 cartilage, placed obliquely on the edge of each valve, and separated by 

 the opening which gives a passage for the byssus. 



I am not certain of this shell having been found fossil, although, I think, 

 I have seen impressions of it in lime-stone. 



CXL. Avicula. A free shell, a little gaping near the beaks, fixing itself 

 by a byssus, and having its valves of unequal size ; the hinge without a 

 tooth, and rather callous. The cartilaginal pit oblong, marginal, and 

 parallel to the edge by which it is sustained. 



