98 DR. p. L. SCLATER ON THE AMERICAN [Mar. 24, 



line of occipital bone not so prominent or strong ; incisors shorter 

 and much straighter ; molars much smaller, but in general outUne 

 similar. 



Lagomys minimus, Lord, sp. nov. 



Sp. char. — Differs from Lepus {Lagomys) princeps of Sir J. 

 Richardson (F. B. A., i. p. 227, pi. 19) in being much smaller. Pre- 

 dominant colour of back dark grey, tinged faintly with umber-yellow, 

 more vivid about the shoulders, but gradually shading off on the 

 sides and belly to dirty white ; feet white, washed over with yellowish 

 brown; ears large, black inside, the outer rounded margin edged 

 with white ; eye very small and intensely black ; whiskers long, and 

 composed of about an equal number of white and black hairs. 



Measurement : Head and body 6 J inches ; head 2 inches ; nose 

 to auditory opening 1| inch; height of ear from behind 1 inch. 



The skull differs in being generally smaller ; the cranial portion 

 of the skull in its superior outline is much narrower and smoother. 

 The nasal bones are shorter and broader, and rounded at their poste- 

 rior articulation, instead of being deeply notched as in L. princeps. 

 Distance from anterior molar to incisors much less ; auditory bullae 

 much smaller. Incisors shorter and straighter, and very deeply 

 grooved on the anterior surface. Molars smaller, but otherwise 

 similar in form. Length of skull 1^ inch. 



General differences from Lagomys princeps — First, v\ being smaller, 

 l|-inch shorter in total length; the ear, measured from behind, |-inch 

 shorter : the colour generally darker, especially the lower third of 

 the back. 



Secondly, in the structural differences of the skull ; for although 

 these differences are not prominent or well defined, yet they are un- 

 questionable variations. 



Thirdly, in the habit of constructing a nest of hay for the winter 

 sleep, and in living at a much greater altitude. 



6. On the American Spine-tailed Swifts of the Genus 

 Ch^tura. By p. L. Sclater, M.A., Ph.D., F.R.S., Se- 

 cretary TO THE Society. 



(Plate XIV.) 



Through the kindness of Professor Baird, of the Smithsonian 

 Institution, Washington, I have lately received for examination a 

 specimen of Chcetura vauxi — the Western Spine-tailed Swift of North 

 America. I have long wished to see an authentic example of this 

 Swift, in order that I might compare it with Mexican skins in my 

 collection which I had referred, not without considerable misgivings, 

 to this species. Upon comparison I find that the skin transmitted 

 by Professor Baird, which was obtained by Dr. C. B. Kennerly when 

 engaged on the North-Western Boundary Survey at Simiahmoo, in 

 July 1852, agrees closely with mine, and I have no doubt of its 

 being of the same species. The range of this bird, therefore, appears 



