108 Miscellaneous. 



trachia, which possess at the same time branchiae and ordinary 

 lungs. The observations of M. Jobort on the intestinal respiration 

 of Callichthys are equally important. — Comptes lieiulus, April 15, 

 1878, p. 935. 



Fossil Mammal from the Jurassic of the Roclcy Mountains. 

 By Prof. 0. C. Marsh. 



One of the most intcrestiug discoveries made in the Rocky- 

 Mountain region is the riglit lower jaw of a small mammal recently 

 received at the Yale-College Museum. The specimen was found in 

 the Atlantosam^us-hediS of the Upper Jurassic, and the associated 

 fossils are mainly Dinosaurs. 



Dryolestes priscus, gen. etsp. nov. 



This specimen is in fair preservation, although most of the teeth 

 have been broken off in removing it from the rock. The penulti- 

 mate molar, however, remains. The shape of the jaw, and the 

 position and character of the teeth, show that the animal was a 

 email marsupial, allied to the existing Opossums {Didelphidoe). The 

 tooth preserved has the same general form as the corresponding 

 molar of Chironectes vane(/utus, Illiger. The angle of the jaw is 

 imperfect, but there are indications that it was inllected. 



The principal dimensions of this specimen are as follows : — 



millim. 



Space occupied by seven posterior teeth 12"5 



Depth of jaw below last molar 4-4 



Transverse diameter 1-8 



Height of crown of penultimate molar 2-0 



Transverse diameter 1'5 



The present specimen indicates an animal about as large as a 

 weasel. It is of special interest, as hitherto no Jurassic mammals 

 have been found in this country. — American Journ. Sci. Sf Arts, 

 June 1878. 



Yale College, New Haven, May 13, 1878. 



On a rare Form of the Hepatic Organ in the Vermes. 

 By M. J. Chaxin. 



In most Vermes, the liver, represented by a cellular layer which 

 lies on the wall of the intestine and covers it for a greater or less 

 extent, seems to differ profoundly from the same organ in the 

 Mollusca, Crustacea, &c. 



The examination of certain types shows, however, that this dis- 

 tinction is far from being so absolute as might be imagined at first 

 eight ; and in some Annelids belonging to the Hirudineae (Pontobdella) 



