ipo PATAGONIAN EXPEDITIONS: ZOOLOGY. 



cable to cinereus, hopelessly at variance with the coloration of either bore- 

 alis or ega. The colour of the body and the size of the ear appear there- 

 fore to me to settle the question, and consequently I still consider 

 Geoffroy's name villosissimus to be applicable to the local form of the 

 ' tres-blanchatre ' Lasiurits cine yens." 



This question, in the abstract, is a small matter, and being averse to 

 controversy, I had concluded to accept Mr. Thomas's argument and de- 

 cision as final, until in compiling the synonymy for the record here given 

 of a Lasiurine bat in Patagonia, it became necessary to examine critically 

 the literature of the subject with a view to determining which of two sup- 

 posed species of Lasiurits [L. borcalis and L. cinereus) was the one 

 represented. 



The outcome has been quite different from what was anticipated, for 

 instead of now referring V. villosissimus to the genus Lasiurus I believe 

 it to be a species of Dasypterus, closely allied to D. ega, and apparently 

 the earliest name for that group. 



The reasons for this conclusion are as follows : The only authors who 

 have described this bat appear to be Azara and Rengger,^ neither of whom 

 gives any account of the dental formula, and their accounts of the external 

 characters are far from satisfactory. From them we gather : ( i ) That it 

 was of about the size of L. boyealis,- having an alar expanse of about 317 

 mm. (2) That it had a rather long, pointed ear,'' much larger and differ- 

 ently shaped from the ear in Lasiurus. {3) The naked edges of the in- 

 terfemoral membrane,^ which do not exist in the Z,. borcalisgro\np, and are 

 only slightly seen in the L. cinereus group. (4) The extreme softness, great 



*Rengger cites under his Vespertilio villosissiinus Geoff. : "Azara's chauve-souris septieme." 



^The measurements given by Azara are: "Longueur, 4 pouces i tiers (11 centimetres 2 

 tiers). Queue, 23 lignes (5 centimetres). Envergure, 11 pouces et demi (31 centimetres)." 



Rengger's measurements : " Die Dimensionen dieser Fledermaus sind : o, 9'" Lange des 

 Kopfes; i" 9'" Lange des Rumpfes ; i" 10'" Lange des Schwanzes ; 11", o Flugweite." 

 Adding together head, body and tail would give a total length of 4)^ pouces, the same as 

 Azara gives; while the "Flugweite" is a half inch less than Azara's "envergure," — a very 

 close agreement. 



' "L'oreille est comme celle du rat ; elle est haute de 7 lignes (i centimetre et demi)," Azara ; 

 " Die Ohren sind etwa zehn Linien lang und fanf Linien breit," Rengger. 



*"C'est de la meme couleur qu' est la membrane de la queue ; cette derniere est velue, 

 excepte dans sa bordure," Azara ; " Die Fliigelhaut, bei ihrer Verbindung mit dem Rumpfe, die 

 Arme und die Interkruralhaut, die letzteren mit Ausnahme des Randes, sind mit feinen kurzen 

 Harchen besetzt," Rengger. 



