552 REPORT OF NATIONAL MUSEUM, 1898. 



tlie i)es is very little longer tbau tbe liftb. All the uugues are acute 

 aud are moderately curved. The hiud legs are remarkably short, not 

 exceeding the fore legs. Extended forwards the extremity of the fourth 

 digit reaches the elbow of the appressed fore leg. Femoral pores twelve 

 on each side; no anal pores. The tail is not long, aud its form is com- 

 pressed, with a Hat inferior surface. The section is a triangle, higher 

 than wide, with the apex narrowly truncate. 



The color is light-brown, with dark umber-brown spots on the supe- 

 rior surface. These spots form, in general, one median and two lateral 

 rows, but as their forms are very irregular this order is obscure. The 

 median dorsals are the largest, and they send branches laterally aud 

 anteroposteriorly, so that the result is rather confused. Dark-brown 

 bands cross the muzzle on the frontonasal plates aud on the frontal, 

 and form a wide U from the frontoparietals passing around the poste- 

 rior edge of the occipitals. Sides of head with rather large brown 

 spots. Inferior surfaces with minute brown spots, which are least 

 numerous on the middle line. Tail with irregular pale spots. 



Measurements. — Total length, 118 mm.; length to posterior edge of 

 occipital plates, 16.2 mm. ; length to axilla, 29 mm. ; length to groiu, 55 

 mm.; length to vent, (JO mm.; width between orbits above, 7 mm.; 

 width at temples, 11.5 mm.; length of forelimb, 17 mm.; length of 

 manus, 8 mm.; length of hind limb, 23 mm.; length of pes, 11 mm.; 

 length of tibia, 7 mm. 



The species which has given occasion for the above discussion is 

 several times as large as the type X. vigilis Baird, and has a different 

 coloration. The digits are shorter. The typical specimen was found 

 by Dr. J. G. Cooper, zoologist of the State Geological Survey of Cali- 

 fornia, and was placed in the collections of the University of California, 

 where I saw it. It was kindly lent me for examination by the authori- 

 ties of the university. The locality from which the speciuien was 

 obtained is San Mcolas Island, one of the Santa Barbara group, coast 

 of California. Subsequently, three specimens were obtained from San 

 Clemente Island, California, by the naturalists of the Albatross. 



The latter display some differences from the typical specimen, as well 

 as among themselves. They all have the temporal plate transversely 

 divided, two into three plates and one into two, the anterior the largest. 

 In the two smaller specimens the occipitals are divided into two equal 

 parts by an oblique suture. In the largest specimen one occipital is 

 undivided, as in the type, and the other is about half divided anteriorly 

 by an incomplete groove. The character of the two rows of supraorbi- 

 tal scales is present in all. The largest specimen is double the size of 

 the largest of the X mgilis known. Without the tail, which is injured, 

 the length is 85 mm.; length to axilla, 38 mm.; to meatus auditor ius, 

 19 mm. 



Three speciuiens from the Santa Barbara Islands were subsequently 

 sent me by Dr. Rivers. In all of tliem the temporals are divided, gen- 



