OF THE MESOZOIC MAMMALIA. 
189 
papers in the American Journal of Science and Arts, which have since appeared fre- 
quently. In 1878 Professor Cope discovered the Puerco Beds, in New Mexico, which 
have subsequently yielded several genera closely allied to the mesozoic forms de- 
scribed by him in the American Naturalist, in the “ Proceedings of the American Philo- 
sophical Society,” and in his large memoir upon the “ Tertiary Vertebrata.” In 1883 
Dr. Lemoine published his valuable memoir upon Neoplagiaulax. In 1884 Professor 
Owen described the remarkable genus Tritylodon, which may prove to be the same as 
Trifjlyplius previously described by Professor Fraas in his work “ Vor der Siindfluth,” 
p. 215. In 1884 Professor Cope published a highly suggestive paper upon the Ter- 
tiary Marsupialia, in which he described Meniscdessus from the Cretaceous, and pointed 
out the ordinal relations of Tritylodon, Polymastodon and Playiaulax. The most 
recent contribution to this subject is an important article by Professor Marsh on the 
“American Jurassic Mammals,” which appeared in April, 1887.^ This marks a very 
great advance in our knowledge of the Jurassic forms previously known, and adds many 
new genera, together with a classification of the American and some of the British forms. ^ 
Preparation of the present memoir. — Through the kindness of the members of 
the Geological Department of the British Museum, I was recently enabled to study 
the fine collection of mesozoic mammals preserved there, which formed the principal 
material for Professor Owen’s monograph. My original intention was simply to re- 
view the types as described by him, but the discovery of new facts followed so rapidly 
that the plan of a systematic revision of these forms gradually resulted. While 
naturally confirming the greater part of Professor Owen’s observations, I was led to 
* The MS.S. for the present memoir was nearly prepared when I received this article. The principal ser- 
vice it afforded me, in connection with the British types, was in correcting my views of the supposed family 
relationship of Stylodon and Athrodofi ; in showing the full pattern of the Stylodon type of molar, and in the 
discovery of the maxillary dentition of Plagiaula.v, which widened the separation of this genus from Bolodon. 
The transitional dentition of the genera Meiiacodon and Tinodon also first suggested to me the relationship of 
Spalacotlierinm to Phascolotherium. The importance of this contribution arises not merely from the variety of 
new forms described, but from the fact that the author has, in many cases, studied both faces of his specimens 
by freeing them from the matrix entirely, whereas most of the British types are still partly imbedded in 
the matrix. 
2 Partial List of Memoirs and Shorter Articles; 
Professor Richard Owen. 
1. Monograph of the Fossil Mammalia of the Mesozoic Formations. Palaeontographical Society, London, 
1871. 
2. On the Skull and Dentition of a Triassic Mammal {Tritylodon longaevus, Owen) from South Africa. 
“ Quarterly Journal of the Geological Society,” 1884. 
Dr. Vidor Lemoine. 
3. Etude sur le Neoplagiaulax de la Faune Eocene inf4rieur des Environs de Reims. Extrait du “ Bulletin 
de le Soci6t4 G^ologique de France.” Fevrier, 1883. 
Professor E. D. Cope. 
4. The Tertiary Marsupialia. “ American Naturalist,” 1884, p. 687. 
Professor 0. C- Marsh. 
5. The American Jurassic Mammals. “American Journal of Science and Arts.” April, 1887. 
6. On the structure and classification of the Mesozoic Mammalia. (Abstract of this memoir). Proc. Phila. 
Acad., June, 1887, 
