522 



REPORT OF NATIONAL MUSEUM, 1898. 



is about one-fifth tbe width of the belly sheet and is generally con- 

 cealed by the folding of the latter over the sides of the dorsal. The 

 two lateral strips of soft skin separate a dorsal and ventral sheet or 

 plate which are very stifl" and firm, the former rather broader than tbe 

 latter. The scales on the sheets are arranged in transverse series, the 

 dorsal, however, with a slightly backward direction on the median line. 

 The scales on the tail are regularly whorled. 



The ])lates on the head are large and regular. There is a long nar- 

 row vertical, concave on each side, wider behind (where it is truncated 



and three sided) than before, 

 where it is two sided and obtuse 

 angled. There are two jjost- 

 frontals, a frontal, and two pairs 

 of short, broad internasal j^lates 

 to the rostral. The frontal is 

 broad, rhomboidal, truncate lat- 

 erally, and separates evenly the 

 postfrontals and intern asals. 

 There is a large inner supra- 

 orbital series of five plates, with 

 a smaller of three in its external 

 concavity. It is bordered exter- 

 nally on the upper edge of the 

 head by six plates. The nos- 

 trils are lateral in a single plate 

 next to the first and second 

 labials, with two small plates 

 behind it, succeeded by a third 

 postnasal, in most specimens 

 divided into two; next comes a 

 large loreal and a smaller ante- 

 orbital to the eye. There are 

 ten upper labials and nine or 

 ten lower. The infraorbitals are 

 two; the postorbitals in two 

 successive series of three and 

 four small plates; then comes four vertical series to the ear. There 

 are three median occipital plates in line with the vertical (sometimes 

 only two), anterior largest, and three plates on either side larger than 

 the rest. The distinction between plates of head and neck is, how- 

 ever, very slightly marked. Above it may be known by the transition 

 from the single occipital plate to the double dorsal series. There is a 

 very slight tendency only to imbrication in the cephalic plate. 



The scales in the dorsal sheet are all conspicuously carinated, the 

 upper ones very obtusely mucronate. There are fourteen ridges and 

 rows of scales on the dorsal plate, all the scales quite equal in size, 



Fig. 93. 



GERRHONOTUS MULTICARINATUS I5LAINVILLE 



=1. 



California. 



C.Ht. No. 7909, U.S.N.M. 



