288 REPORT OF NATIONAL MUSEUM, 1.S98. 



Professor liaird (listing iiislied a llolbrooJda affinis as distinct from 

 the H. texana. but I find the following note in liis manuscrix^t: 



The diiference between the typical II. texana autl the supposed species II. affinia 

 will he fouud indicated, as far as I have been able to appreciate them, under th(5 

 latter head. I must confess, however, a very groat difficulty in assigning many 

 specimens to one rather than to another of these species. 



He then defines the typical H. texana as follows : 



Legs rather short, the hind foot little more than cue-third length of head and 

 body; femoral pores, twelve or thirteen. Above olive gray, with ten dorsal series of 

 rounded dusky blotches, which on the tail behind anus become six or eight rings, 

 intensely black below. Posterior half of sides with ten long crescents widening 

 below, the posterior twice its width from the groin; the interspace and border lighter 

 on the sides above, but below and on the belly blue. .Sides anterior to the crescent 

 s^iotted Avith whitish. Chin strongly mottled with blue and white; thigh behind 

 with a longitudinal plumbeous stripe; a black spot on shoulder, and one or two 

 behind it on humerus. Female with the lateral crescents ^replaced by oval spots. 



In some specimens of H. texana (Cat. ISTo. 20(39) there is a tendency to 

 a continuation of the lateral crescent in a series of rapidly diminishing, 

 broad, sub(iuadrate, plumbeous, crescentic blotches close together, of 

 which four may be counted to above insertion of hind legs, continued 

 as broad stripe ahnost halfway along the side of tail. This is more 

 evident in females than males. 



The HolbrooMa a^nis is defined as follows : 



This species differs from S. iexana in several points, chief among 

 theoi the larger size of the dorsal scales and the greater length of limbs. 

 Those in H. texana are scarcely larger on the back than on the sides; 

 and the arrangement into oblique series can hardly be observed. There 

 are about one hundred and seventy-five of the scales from head to above 

 anus. In IT. affinis there are one hundred and fifty scales in the same 

 distance; larger and more regularly rhomboidal. The free portion of 

 tlie hind toe in texana is only about li the length of the head above 

 from snout to end of occiput, and equal to the length from snout to end 

 of jaws or of large lateral plates on the cheeks. In H, affinis this is 

 one and one-half times the length of head and one and one-fourth or 

 one and one third times length of side of jaw. The scales on the upper 

 face of the thigh appear more abruptly sumller than the anterior ones 

 in texana than in affinis. 



There aj^pears to be little difference in coloration. The bands beneath 

 the tail appear more distinct in H. texana, more tinged with the blue of 

 sides and chin deeper. The crescents on the sides are farther back in 

 JI. affimis; the posteriors are separated from the groin only by its own 

 width, instead of twice this amount. The edge of the anterior crescent 

 in texana. reaches about two-fifths from fore to hind leg, instead oXouly 

 about one-third, as in affinis. H, texana exhibits no trace of a third cres- 

 cent springing from the groin. It, however, has a conspicuous black 

 spot on the shoulder, with one or two behind it on the anterior face of 

 humerus, very indistinctly seen in specimens of H. affinis. 



