400 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



No. No, No. No. No. 



15,222. 15396. 15,572. 15365. 15,266. 

 Cranium, length, occipital condyle to rim 



of orbit .056 



Face, length, orbit to end of rostrum. . . . .048 



Occiput, height .030 



" width at base .039 



Skull, width behind zygomatic process . . .039 .040 



" in interorbital region .030 -032 



Rostrum, width at anterior end 019 .018 .021 



Mandible, length from condyle .068 .070 



" depth below m T .013 .014 .01 5 



NEOREOMYS PACHYRHYNCHUS (Ameghino). 

 Pseudoneoreomys pachyrhynchus Amegh. ; Rev. Argent, de Hist. Nat., 



T. I, 1891, p. 300. 



Certain skulls in the collections are so large and heavy that they prob- 

 ably represent a species different from the preceding one, especially as 

 they are not closely connected by transitional forms with the average in- 

 dividuals of N. australis. To these large animals the name N. pachy- 

 rhynchus Amegh., may be applied, as the broad and heavy rostrum is a 

 very characteristic feature. The type specimen appears to be rather 

 smaller than the somewhat crushed and distorted skull in the collection 

 of the American Museum of Natural History (No. 9,130) from which the 

 following measurements are taken. The type is, however, so incomplete 

 as to permit little direct comparison. 



MEASUREMENTS. 

 Upper dentition, length 059 Occiput, height 03 2 



" " pA-mi 024 " width at base 040 



Upper incisor, width 006 Skull, width behind zygomata 044 



" " thickness 006 " " in interorbital region 036 



Skull, length over all 109 Rostrum, width at anterior end 028 



There remain two species of Neoreomys, which Ameghino has described 

 and which are probably valid, though as each is known only from the 

 type specimen, it is possible that they are merely abnormal individuals. 



NEOREOMYS DECISUS, Ameghino. 

 Neoreomys decisus Amegh. ; Enumeracion sistemat., etc. ; 1887, p. 11. 



In size this species is much the same as N. australis, from which it is 

 distinguished by the lower incisor. This tooth has a plane, instead of 



