Miscellaneous, 389 



outer chamber of certain Ammonites, as for exam})le, in A. Jasoni. 

 In the phragmocone of the Belemnoteuthis the peristome is entire. 



Another interesting part of the structure of the Belemnite, not 

 previously detected, is also shown in the same specimen, as well as 

 in many other examples found in the Oxford clay near Trowbridge ; 

 namely, a calcareous shelly periosteum or capsule, which invests the 

 guard, and expands upwards into a horny sheath or receptacle, that 

 surrounds the basal chamber of the phragmocone in which the viscera 

 were probably contained. This receptacle was formerly supposed to 

 originate from within the alveolus of the guard. Mr. Miller, many 

 years ago, inferred the existence of a vascular integument around 

 the guard from the meandring impressions of blood-vessels obser- 

 vable on the surface of some specimens ; but the presence of a cal- 

 careo-corneous capsule or sheath investing the guard, and expanding 

 into a horny receptacle, has not till now been demonstrated. 



The author considers the facts described as proving that the ce- 

 phalopod of the Belemnite was entirely distinct from the Belemno- 

 teuthis ; and that the muscular mantle, cephalic arms, and other 

 parts referred by Professor Owen to the former, exclusively belong 

 to the latter genus. 



He concludes that the remains of at least three genera of naked 

 Cephalopoda occur in the argillaceous deposits of the oolite in Wilt- 

 shire ; namely, the first or true Calamary, with a horny dorsal gla- 

 dius or pen ; the second, the Belemnoteuthis, or a decapod with unci- 

 nated cephalic arms, ink-bag, pallial fins, and a corneo-calcareous 

 phragmocone ; and the third, the Belemnite, which possessed a phrag- 

 mocone having the apical part implanted in the cavity or alveolus of 

 a guard or osselet, which in its original state resembled in substance 

 the sepiostaire of the Cuttle-fish, but is generally found mineralized 

 by calcareous spar ; and the peristome, possessing two or more elon- 

 gated shelly processes ; both the guard and the phragmocone being 

 invested with a corneo-calcareous capsule or receptacle. He observes, 

 lastly, that the body and other soft parts of the cephalopod of the 

 Belemnite are at present unknown. The author's communication 

 was illustrated by drawings, and accompanied by the specimens 

 above described. 



MISCELLANEOUS. 



On a new genus and species of Fossil Ruminantia, Poebrotherium 

 Wilsoni. By Joseph Leidy, M.D. 



Indirectly through Mr. J. S. Phillips and the influence of Dr. S. 

 G. Morton, the Academy has become the depositary of a valuable 

 and unique fossil, received through Dr. S. D. Culbertson of Cham- 

 bersburg. Pa., from Mr. Joseph Culbertson. 



As first received, it consisted of a mass of argillaceous limestone, 

 having one side of a cranium of an animal exposed to view, which, 

 by the patience of Dr. T. A. Wilson, was relieved of its matrix ; and 



