200 



[December, 



Locality. San Luis Obispo, California. 



This huge species is imbedded in friable limestone which contains abundance 

 of silicious sand rounded by attrition. No other fossil can be detected in the 

 portions of limestone which accompany the specimens. 



Cretaceous Species. 

 Pholas. 



Pholas pectorosa. Ovate-cuneate ; anteriorly inflated, contracted in the 

 middle ; posterior side cuneiform ; disk with radiating ribs, largest anteriorly, 

 and interrupted by concentric furrows ; anterior side yery short, margin ob- 

 tusely rounded or subtruncated ; basal margin rounded anteriorly, contracted 

 medially, straight posteriorly. 



Locality. Tinton Falls, Monmouth Co., N. J. 



This rare species was found by the late Lardner Vanuxem. It is a cast, on 

 the right valve of which an impressed line runs obliquely from the apex, while 

 on the opposite valve there is a corresponding furrow, and the three ribs nearest 

 the posterior end are more remote from each other, than in the right valve. 



Inocer amies Senseni. 



Inocebamus, Sow. 



Rounded ; both valves profoundly curved ; beaks involute, the volutions of 

 the larger valve, 3, contiguous in both valves. Length 1^ inches ; width 1^ in. 

 Locality. Missouri river, Nebraska. Mr. Senseny. 



Tnoceramus perovalis. Oval, convex, slightly oblique ; beaks medial, both 

 dorsal margins equally declining; basal margin acutely rounded: surface 

 with obsolete concentric undulations. Height about 1^ inches j length less 

 than the height. 



Locality. Chesapeake and Delaware Canal. Mr. Vanuxem. 



The Committee on papers by Dr. Woodhouse namely, "Descrip- 

 tion of two new species of Pouched Rats,'' and " Description of a new 

 species of Struthus/' reported in favor of publication in the Pro- 

 ceedings. 



Description of a New Species of Pouched Rat, of the Genus Perogna- 



thus, Wied. 



By S. W. W. Woodhouse, M. D. 



Peuognathus penecillatus. 



Characters. Above yellowish brown, beneath white, tail longer than the 

 head and body, penecillate, with bright brown hair. 



Form. Head of moderate size, not easily distinguished from the neck ; 

 incisors small and partially exposed, upper ones sulcate in the middle. Nose 

 small and rather pointed, extending some distance beyond the incisors ; whiskers 

 light brown, irregularly mixed with black; eyes dark brown, and of moderate 

 size; ears nearly round and moderate, almost naked anteriorly and covered 

 posteriorly with fine brown fur; the tragus and antitragus are quite prominent. 

 The external meatus is protected by a tuft of short black bristles extending 

 across the ear. Tail about one and a quarter inches longer than the head and 

 body, round, gradually tapering, and covered with hair; on the superior and 

 middle portion commences a row of long silky hairs, which gradually increase 

 in width until they form a tuft at the end. Fore legs short, feet small, with 

 four well developed toes and a short thumb, which is armed with a nail ; 

 palms naked. Hind legs and feet long, having five toes, terminated by nails. 

 Feet and toes covered with short fine fur ; soles naked. The fur longer on the 

 back than on the belly; it is thick, soft and silky. 



