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THK HATRACIIIA OK NORTH AMERICA. 



187 



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tail is that of A. luffuhris, ami not tliat of ^l. iivdnus. lUit one speci- 

 nu'ii has come under my oUservalion, as follows: 

 No. 071>4i 1 si»ecimen ; Fort IJmpiiUii, Orcfjon ; Dr. Vollen. 



AUTODAX liiCANL'.S C.ipc. 



I'h'hodini ii'caiiHs Copo, Proccod. Ac. Pliila. 188!}, p. 21. 



.Iiniidct ii'ii'iiis Cit\K', I'rocciMl. Aiiicr. I'liilosoph. Sdc, 188!), p. ^viC). 



A I'liily f^rown imlividtial of tins speeics i)resents the followiuf;' char- 

 acters: The form is ratlier robust, and the head is distiii<;nished from 

 the neck by tiie swollen temporal mnscles. The muzzle is short and 

 wiile, with roiiuded border, and is not so contracted as in the.l. liiiia- 

 />//v. The len<;th from the end of the muzzle to the axilla enters that 

 IVom the latter to the t-ioin one and a half times. The tail isof moderate 

 Icnjith, equiilin,n' tlmt of the body (includinf? vent) nearly to the thora(!ic 

 fbhl. TIh! width of the head enters the lenj>th from end of muzzh? to 

 j;ioin live and one half times— a proportion intermediate between tho.se 

 exhibited by the two other species of the fi'enus. The limbs are rather 

 robust, and when ai)pressed to t!,.; .sides leave an interval of three 

 iMler<;ostal spa(;es. 



The top of the head is flat, and the least interorbital width is ecpial 

 to the lenj^tii from the eye to th(^ end of the muzzle and to the space 

 inclo.si'd between the external borders of the external nares. The 

 commissure of the mouth rises behiml the line of the orbit as in the.l. 

 Iii(/iihri^. The muzzle does not project lieyond the mouth, as it does in 

 .1. luiftthris. The internal nares are very small. The tongue is lar<>e 

 and antero posteriorly oval, and is t'xtensively free at the sides. The 

 vomero palatine teeth are in two short rows of three or four teeth each, 

 which (M)mnK'nce behind the internal nares, ou a liiu' with their inter- 

 nal borders, and converge, with slij;hi posterior inclination, without 

 meetinfj. The patch of parasphenoid teeth is wide and subtruneate in 

 front, and is undivided except towards the i)osterior ])ortion. The 

 larjxe teeth of the Jaws are not so well developed as in the .1. int/Kbris^ 

 ar(^ nH)re sleinler in form, and not so numerous. They <!onstitut«', the 

 entire arnniture of the dentary bone, occupying; only the anteri(U' half. 

 1 <!ount only four of then), and they are movable; that is, iiunniture. 

 1 find no fixed oiu>s of the larji'cr size in the uppi'i- jaw. Three or four 

 of the posterior imixillary teeth are like those (»f the dentary bone, but 

 Ihey ;4iadiiate anteriorly into teeth of the usual type. An examina- 

 tion of otherspeciuuinswill be necessai'y toascertain whether these teeth 

 i»econu5 permanent or not, or whether they are developments of the 

 lireedin<>' season. The larj;e temi)oral muscles, curved coi: nissure of 

 the Mn)Uth, etc., so re.send)l(^ the correspondiiiii' parts in the .1. liiijiihriii, 

 that I suppose their i)ermanentdtMital characters to be alike. Thennix- 

 ill-ry bone projects abruptly downwards behind th(^ last nmxillary 

 lOoth, formiuff a snn)(>th eil;i'e. as in A. hifiKhris. 



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