190 MR. O. THOMAS ON THE 



Plate XVII. 



Fig. 1. Skull of Stcatornis caripensis, adult, side view. 



2. Skull, upper view. 



3. „ lower view. 



4. Lower jaw, upper view. 



Plate XVI II, 

 Fig. 1. Skull, end view. 



2. Os hyoides, upper view. 



3. Atlas, front view. 



4. Axis, front view. 



5. Last dorsal vertebra, front view. 



6. „ „ „ hind view. 



7. Shoulder-girdle and sternum, lower view. 



8. „ ,, ,, side view. 



Plate XIX. 



Fig. 1. Cervical and dorsal vertebras and ribs, side view. 

 1 a. Last four cervical ribs. 

 2. Pelvis and caudal vertebriB, side view. 



[Apr. 2, 



4. Left leg, side view. 



5. Part of same, front view. 



upper view. 



Plate XX. 



Fig. 



Left wing, outer view. 

 Part of same, inner view. 

 Tarso-metatarsus, top view. 

 Tibia, lower part, front view. 



5. Ankle-joint, side view. 



6. Pelvis, lower view. 



Size of fig. 

 1^ diam. 



1^ diam. 

 2 diam. 



9> 

 tt 



Nat. size. 

 Nat. size. 



Nat. size. 



2 diam. 

 I) 



>f 

 Nat. size. 



3. Preliminary Notes on the Characters and Synonymy of 

 the different Species of Otter. By Oldfield Thomas, 

 Natural History Museum. 



[Received March 13, 1889.] 



One of the most interesting and at the same time most difficult 

 groups of Mammals is that of the Otters, a group which many 

 zoologists have tried to work out wholly or in part, but which, owing 

 to the striking resemblance of the species to one another, to the 

 difficulties of obtaining large series, and to the variability of the 

 different forms, has remained to this day in a terrible state of con- 

 fusion, both as to systematic arrangement and nomenclature. 



The present paper does not pretend to be anything like a complete 

 monograph of the group, but only attempts to clear up such points 

 in the history of the species as are at present capable of elucidation, 

 while leaving for future investigation many questions which cannot 

 be settled for want of still further material. 



In connexion with this paper I have to thank sincerely Dr. F. A. 

 Jentiuk, of Ley den. Prof. Pouchet and Mons. J. Huet, of Paris, 



