POISONOUS SNAKES OF NORTH AMERICA. 455 



ground color, 1^ scales wide. On the posterior fourth of the total 

 length they form brown cross bands; 5 upon the tail are black on a 

 very light ground, as in C. atrox. Anteriorly there is an ill-defined 

 series of spots which are opposite those of the dorsal line. A yellow 

 band extends from the nasal plates anterior to the eye, involving from 

 the ninth to the last superior labial. Superior to this is a brown band 

 extending from the eye and ceasing on a line with tbe angle of the 

 mouth. Some indistinct brown marks on the top of the head are 

 arranged as follows: One on the inner border of each superciliary; 3 

 posterior to these, the median short and broad; 4 further posterior, the 

 median pair longer, diverging, reaching the neck. 



Variation. — The characters of scutellation hitherto relied upon for 

 distinction between C. mitcUellii and G. pyrrhus, viz, the breaking up of 

 the large horizontal preocular of the former into 2 or more " loreals, " does 

 not hold, as shown by specimens more recently received. Mr. Charles 

 Orcutt has sent us a specimen from the Colorado Desert, San Diego 



Fig. 69. Fig. 70. 



HEAD OF CROTALUS MITCHELLII, TOP VIEW. HEAD OF CEOTALUS MITCHELLII, SIDE VIEW. 



Cat. No. 12625, U. S. N. M. Cut. No. 12625, U. S. N. M. 



County, Cal. (U. S. Nat. Mus., No. 1(5353), which is in all other respects 

 almost identical with Belding's specimen from La Paz, Lower California, 

 (Ko. 12625), but with the preocular on one side divided completely; on 

 the other side, however, only with a faint indication of a division, while 

 another from the same locality has it divided on both sides. These 

 specimens I formerly identified as G. pyrrhus on this account, especially 

 as the specimen of so-called G. pyrrhus from the Mojave Desert, Califor- 

 nia, (No. 8669), has the preocular divided on both sides exactly as No. 

 16501 and the left side of No. 16353. This specimen is, therefore, also 

 a true G. mitchellii. The fiice scutellation of the type of G. pyrrhus (No. 

 6606) is practically identical with that of Dr, Loew's specimen, from 

 the Mojave Desert, and the only difference which I can see consists in 

 the deep reddish color, a difference which can not be regarded as more 

 than subspeciflc, if indeed it is more than an individual variation. In 

 the California and Lower California specimens the ground color is j)ale 

 yellowish, almost white. 



While reading the proofs of this article 1 received a paper by Mr. 

 John van Denburgh (Proc. Cal. Acad. Sc. (2) iv, pp. 150-4:55), who, from 

 an examination of 10 specimens in the California Academy from Lower 

 California, comes to the same conclusion. In these the granules be- 

 tween the nasal and the rostral occur indiscriminately, in one or two 



