350 On some new fossil Mammalia from the Freshwater Strata. 



examination of the celebrated freshwater cliff at Hordwell in 

 Hampshire, and upon quitting England in the early part of this 

 year Mr. Wood intrusted to me for publication the new fossils 

 which he had discovered, accompanied by manuscript notes. To 

 these he requested I would append such remarks as a more full 

 examination of the respective specimens might enable me to 

 furnish. 



Of the remains in question referable to the Mammalia, the most 

 instructive specimen is an imperfect cranium of a Pachydermatous 

 quadruped, for which Mr. Wood proposes the generic name Mi- 

 crochoerus. It comes very near Hyracotherium in the general 

 aspect of the molar teeth, but its size could hardly have exceeded 

 that of the hedgehog (Erinaceus europmus). It had moreover 

 no interspace between the second and first spurious molar, nor 

 between this last-named tooth and that which in Hyracotherium 

 Prof. Owen regards as a canine. The last molar also differs very 

 decidedly in shape from that of Hyracotherium, but until more 

 species of this group are known, generic distinctions can only be 

 regarded as provisional, and in the present case the characters 

 assumed as generic may hereafter prove to be only specific. Most 

 fortunately one ramus of the lower jaw was found with the above, 

 demonstrating that Microchcerus has that remarkable prolonga- 

 tion backwards of the angle so strikingly displayed in Chceropo- 

 tamus. 



Mr. Waterhouse takes the following view of the dental formula 

 of this genus : — 



Incisors \Z\j canines qZq > ^ se molars 434; true molars 333; 



= 34 



1 st. % The specific name of erinaceus is proposed by Mr. Wood 

 for this new addition to British fossil Mammalia. 



2nd. Part of the upper jaw of a very small nondescript mammal, 

 with highly complicated molar teeth, clearly insectivorous, but not 

 sufficiently perfect to decide upon its generic relations*. 



3rd. A trifid mammalian tooth cleft nearly to the base of its 

 crown as in the genus Stenorhynchus, and which I believe to be 

 the tooth of a seal. 



4th. A mammalian tooth remarkably compressed, with a single 

 lateral lobe. I think this may also be referable to a seal. 



* Mr. Flower of Croydon, stimulated by Mr. Wood's success, pursued the 

 investigation of the Hordwell cliff, and along with other interesting fossils 

 obtained a considerable portion of the lower jaw of a small insectivorous 

 mammal, which he was so obliging as to lend to Mr. Wood, that it 

 might be described along with the new mammalia previously discovered. 

 For this fossil I suggested at the Meeting of the British Association the pro- 

 visional generic term Spalacodon. 



