210 BULLETIN 15 4, UNITED STATES NATIONAL MUSEUM 



1 ill 1.") bpL'ciuK'i'.s; supraocular graiiuk's fxteiidiiig- forward to the 

 middle of the third supraocular in 13 specimens, and to the anterior 

 border of the third supraocular in 4 specimens. 



Variation. — A total of V6 intergrades betAveen canus and tnartyria 

 were collected by Mr. Slevin on South San Lorenzo Island. Data 

 from these foUoAvs: Body, 54-78 mm.; tail, 132-175; total length, 

 193-248; length of tail as percentage of total length, 68.4-74.5; width 

 of head, 8-12; width of head as percentage of body length, 13.0-15.6; 

 hind leg, 40-53; length of hind leg as percentage of body length. 

 62-78; supraoculars 4; supraocular granules extending forward to 

 the middle of the third supraocular in 12 specimens, and to the an- 

 terior border of the third supraocular in one specimen ; femoral pores 

 17-21. 



A comparison of the data given for these intergrades with that 

 presented for typical canus and typical mattyr'tH^ especially in regard 

 to the more definite percentage computations, is an excellent means 

 of demonstrating their close relationship. In no case is there a 

 significant divergence in the intermediates from the presumed " nor- 

 mal " of the other two groups. 



The 13 specimens from South San Lorenzo Island are exact color 

 intermediates. Four large specimens (C.A.S. Nos. 51262, 51264, 

 51266, 51269) are identical with martyris in coloration, with the 

 exception that the anterior upper labials are light in one (No. 

 51264). Of the smaller specimens, three have definitely black 

 chests (Nos. 51263, 51265, 51268), but one (No. 51287) has a very 

 light chest. Another specimen (No. 51272) is identical with canus. 

 The series as a whole is decidedly darker than canus.^ but distinctly 

 lighter than martyris. 



Range. — The typical form is confined to two small islands in the 

 Gulf of California. These are Sal Si Pucdes and North San 

 Lorenzo Islands (Van Denburgh and Slevin, 1921a, p. 97, C.A.S.) • 

 Intergrades with martyris are found on South San Lorenzo Island 

 (Van Denburgh, 1922, p. 541, C.A.S.). 



Habitat and habits. — This species is fairly common on Sal Si 

 Puedes Island according to Van Denburgh (1922, p. 542). Most 

 of the specimens collected were taken under the low-growing shrubs 

 in the bottom of the small arroyos. Their coloration gave them 

 excellent protection, as it blended perfectly with the slate blue rocks 

 which cover the island. 



Affinities. — This form is subspecifically allied to both tessellatus 

 and martyris^ and, as indicated above, intermediates between tessel- 

 latus and canus.) and betw^een canus and iiiartyris., have been ex- 

 amined. The transition in each case is but a step. The general 

 relationships of canus are the same as those of martyris and have 

 Ijcen discussed at length under the affinities of that form (p. 207). 



