MAMMALIA. 



45 



uous tooth is displaced and succeeded vertically by a second molar. These fossil 

 teeth, one anterior, the other posterior, were discovered in a marl deposit of the 

 " Jackson epoch" (Middle Eocene) in Claiborne, Alabama, and are now in the Ana- 

 tomical Museum of Berlin. Size, 6x4. Price, $1.00. 



No. 177. Zeuglodon hydrarchus, Carus. 



Skull. The dis- 

 tinctive feature of 

 this species is this, 

 that "while in the 

 Z. ceto'ides there is 

 in the upper jaw a 



conical tooth having two roots which may pass for a canine or a premolar, in the 

 Z. hydrarchus there are two such abnormal canines. So that its dental formula 

 is : i 3 c ? 2 to f=19- This skull was found at the same locality as the preced- 

 ing, and belongs to the Tylerian Museum at Haarlem. Size, 32 x 13. Price, $7.00. 



No. 178. Rhizoprion Schinzi. 



Head, This Cetacean — some- 

 what allied in form to the modern 

 Porpoise — is from the Middle Terti- 

 ary beds of Central France, and is 

 preserved in the Museum of Natural 

 History of Lyons. 



Size, 26 x 10. Price, £10.00. 



No. 179. Balaenodon gibbosus, Owen. 



Cetotolites, two specimens. These fossil tympanic bones belong to a large, 

 extinct Whale, which, probably like some contemporary quadrupeds, retained 

 fully developed characters which are embryonic and transitory iu existing Ceta- 

 ceans. They were found in the Red Crag (Pliocene) of Suffolk, England ; but as 

 they are water-worn and rolled, and were doubtless washed out of previous strata. 

 The original specimens belong to the Ward Museum in the University of Roches- 

 ter. Price, $1.00. 



No. 180. Ccetns Emmonsi, Leidy. 



Tooth. This remarkable dental form, having a resemblance to the canine of 

 the Hippopotamus, was found in the Older Miocene of White River, Upper Mis- 

 souri region. Size, 9x4. Price, $1.25. 



Order 9 — Marsupialia. 



The Marsupials possess a peculiar feature which, places them lowest 

 in the Mammalian series. This feature is the premature production of 

 their young, which are matured in a pouch, supported by two peculiar 



