120 



MR. OLDPIELD THOMAS OX THE MAMMALS- 



Explanation af Lettering on I'ext-figures. 



mandibular arch. 



mandibular branch of trigeminal. 



mesoblast of mandibular arch. 



myotome 1-6. 



mouth. 



maxillary branch of trigeminal. 



neural arch. 



notochord. 



nasal sac. 



occipital arch. 



optic cup. 



optic nerve. 



pericardium. 



preoccipital arch. 



preorbital process. 



profundus nerve. 



pronephros. 



quadrate. 



metaotic somite, 

 hyomandibular somite, 

 hind limit of skull, 

 mandibular somite, 

 superior ophthalmic nerve, 

 first spinal lierve. 

 f, second spinal nerve, dorsal and 

 ventral root, 

 spinal ganglion, 

 spiracular slit, 

 ventral i-oot of spinal nerve, 

 trabecula ci'anii. 

 trigeminal ganglion, 

 trabecular parachordal, 

 tectum synoticum. 

 vagus nerve. 



ventral lateral line nerve, 

 roots of vagus and glossopharyn- 

 geal, 

 ventral root. 



9. The Mammals o£ the Tenth Edition o£ Liunsens ; an 

 Attempt to fix the Types of the Genera and the exact 

 Bases and Localities of the Species. By Oldfield 

 Thomas, F.R.S., F.Z.S. 



[Received November 29, 1910: Eead December 13, 1910.] 



The tenth edition of Linne's 'Systema Naturae' is the recognized 

 basis and commencement of all systematic zoological work, but 

 doubtful questions in its interpretation are very numerous, and 

 there is probably nothing more desired, by mammalogists at least, 

 than a methodical examination of this important work, with 

 suggestions, obtained on some definite and uniform system, foi- the 

 identification of its types, both of genera and species. 



For many years I have taken a very great interest in this 

 subject, a,nd have now ventured to prepaie the present paper, 

 with the hope that it may be of service to other mammalogists less 

 favourably .situated as regards book.s and specimens than 1 have 



