1908.] DR. KNUD AXDERSE?^ ON BATS. 305 



to prevent a confusion of these two bats Avhich, though similai- in 

 the points mentioned, are widely distinct species : — 



The skull of A. 2yhceotis is probably of the toltecus pattei-n ; 

 in A. nanus (and its larger relative A. tiM-pls) the rostrum 

 is peculiarly flattened and slightly bent upwards ; the profile 

 of the names skull is therefore very diflferent from that of 

 the phceotis skull. In A. pkceotis the proportionate length of the 

 bony palate is quite as in toltecus and allied species : measured 

 from palation to hinder border of incisive foramina, longer than, 

 or at least equal to, distance from palation to basiun ; in nanus 

 (and tmyis) the palate is shortened : its length (palation to 

 incisive foramina) shorter than the post-palatal portion, from 

 palation to basion. The skull of nanus is, on the whole, 

 distinctly smaller than that of phceotis. All these differences 

 have been confirmed by Dr. Lyon (in litt.), who kindly compared 

 a skull of my A. nanus (U.S. N. M. no. 51765; Colima) with 

 the type skull of Miller's A. phceotis. — Also externally the two 

 species, in spite of all similarity, are distinguishable : although 

 the forearm in phceotis appears to have the same length as in a 

 large nctmos, the metacai'pals are conspicuously longer ; third 

 metacarpal 37'3 mm., against 32*2-35 mm. in a series of nanus; 

 also the proximal phalanges are a little longer in 2)^iceotis. 



Elliot's Dermanurco jucuncla,^ 1906. — Type locality: Achotal, 

 State of Vera Cruz, Mexico. Described from one example, with 

 skull. — -According to Elliot, it is "allied to D. quaclrivittcitum 

 from South America, but is smaller, with a considerably smaller 

 skvill," and " the nose behind the nose-leaf whitish " ; supraorbital 

 stripes "very conspicuous," infraorbital stripes "very indistinct." 



Professor Elliot has kindly informed me that the distance from 

 palation to the hinder border of the incisive foramina is slightly 

 greater than the distance from palation to basion (thus quite as in 

 the ordinary Artibeus skull, not as in A. nanus and tutyis), and 

 given me some measurements of the skull, teeth, and wing (see 

 table p. 309). From these measurements it is evident that the 

 size of the skull and teeth is precisely as in A. phceotis. The 

 foreann measures "41*8 mm." (Elliot in litt.; not 43 mm. as 

 stated in the published description), as against " 37*9 mm." (Lyon) 

 \\\ phceotis, a discrepancy of 3'9 mm.; but Lyon has undoubtedly 

 measured the forearm of phceotis to the distal end of the radius 

 (if not, the difference between the length of the forearm and the 

 third metacarpal, respectively 37'9 and 37*3 mm., would certainly 

 be greater), and if Elliot, on the other hand, has measured the 

 forearm of jucunclcc to the front curve of the carpus, then 

 the discrepancy is reduced to about 3 mm., a very reasonable 

 amount of individual variation in an Artibeus of this size ; 

 further, it should be noticed that Elliot's measurement of the 

 third metacarpal is exactly (to a fraction of a millimetre !) like 

 that of A. j)hceotis, viz. 37*3 mm., and also the length of the 

 phalanges of the third, fourth, and fifth digits practically as in 

 phceotis. — The white patch behind the nose-leaf mentioned by 



20* 



