108 OPHIDIA. 



the body. On the head and beneath, the general hue is lighter, owing 

 to a greater development of the light margin of the scales and the 

 isolation of their central dark sjDot. 



Log. — This species inhabits the coast of Peru ; the specimen de- 

 scribed was collected in the rafters of houses at Callao. 



Plate XV, fig. 7, represents the head of Sahrina tessellata, viewed 

 in profile. 



Fig. 8, is an upper view of the same ; and 



Eig. 9, an under view, exhibiting the outline and shape of the mouth. 



All these figures are magnified about four times, in order to show 

 more distinctly the various plates. 



Genus CYLINDROPHIS, Wagl. 



Gen. Char. — In this genus there are teeth in the upper and lower 

 jaws, on the palatine and pterygoid bones; none on the premaxil- 

 laries. The pupil is circular; the nostril situated within one plate. 

 The internasal plates are absent; the cephalic ones, seven in number. 

 Neither a loral nor any anteorbitals ;.one postorbital only. The 

 scales are smooth, surrounding the entire body, so that there are 

 no abdominal scutellse, transversely elongated, contrasting with the 

 dorsal scales. The subcaudal scutelloe are entire, and very similar 

 to the ordinary scales of the upper region. 



Syn. — Ci/lindrojihis, V^AQiu Natur. Syst. Ampb. 1830, 195. — Du3i. & Bibr. Erp. 

 g^D. VI, 1844, 590. 



Observ. — In drawing up the characters of the genus Cijlindrophis, 

 ^\Q have had for our sole guidance the species recorded below, and 

 therefore may have to be remodelled so as to include other species. 

 Then, again, the question will recur as to the validity of the genus 

 llysia, of Hemprich, a question to be settled by the comparative study 

 of all the species referred to both of these genera. 



