206 MR. J. LEWIS BONHOTE OX THE [NoV. 15, 



In the first group, which may be called the 



Ladacensis Group, the incisive and palatal foramina are sepa- 

 rate and distinct, the lower and postei-ior portions of the 

 pi'a-"maxilla?, although very thin, meeting in the middle line. 

 In the second group, which may be known as the 



Riifescens Group, there is no bony division between the incisive 

 and palatal foramina, but the incisive foramen is narrow 

 and slightly constricted at its posterior end, Avhence it 

 suddenly broadens out into wdiat represents a large palatal 

 i'oraiucn. 

 Lastly, there is the 



Ciirzoniae Group, in which the large single foramen is practically 



triangular in shape, w'ith little or no constriction to mark 



the division between the incisive and palatal foramina. 



The following is a list of all the names belonging to this genus 



under the special groups to Avhich they belong, as Avell as the 



type-locality from which they came. In the body of the paper, 



however, I have considered some of them as synonyms or 



subspecies. 



I. Ladacensis Group. 



Type,- Locality. 



OcJiotona alpina Altai. 



0. hyperhorea N.E. Siberia . 



0. normalis 1 



0. ferruginea I ^o^^^h of K. Maia, N.E. Siberia. 



0. cinereojiava 



0. fusca J 



0. Uttorcdis S. of C. Tschukosky. 



0. ladacensis Ladak. 



0. ogotona Beyond L. Baikal and Desert of 



0. erytkrotis Gannsu, N. Thibet. [Gobi. 



0. rutila Vernoe Mts. , Turkestan . 



II. Eufescens Group. 



0. rufescens Cabul, Afghanistan. 



O.hosloivi N.Thibet. 



0. jnisilla S.E. Russia and S.W. Siberia. 



0. wardi Kashmir. 



III. Curzoniae Group. 

 0. curzonice Sikkim. 



0. mekmostoma Kuku-noor, S. Thibet. 



0. daurica Dauria. 



0. macrotis Doha, Turkestan. 



0. aurita Pangong Lake, Ladak. 



0. grisea Kuenluen R., S. of Sanga Pass. 



O.roylei Choor Mts. 



0. nepalensis Nepal. 



0. hodgsoni Ladak. 



0. tihetana Moupiu, N.W. Szechuen. 



