ONYCHOCEPHALUS ACUTUS. 177 



ONYCHOCEPHALUS, Diim. Sf Bibr. 



Snout covered with large shields ; rostral with a trenchant anterior edge ; 

 praeocular present ; nostril at the lower side of the snout. 



Only one species is found in British India. 



ONYCHOCEPHALUS ACUTUS. (Plate XVI. fig. A.) 



Onychocephalus acutus, Durn. ^ Bibr. vi. p. 333. 

 Typhi ops russellii, Ch-ay, Lizards, p. 132. 



Onychocephalus westermaniii, Liitken, in Naturhist. Foren. Vidensk, Meddel. 1863, Nov. 29, 

 tab. 1. fig. 5. 



Rostral shield exceedingly large, covering nearly the whole of the upper surface of the 

 head ; it has a sharp edge in front, which is slightly bent downwards and produced into a 

 rather acute point ; it is so much dilated that its lateral margin touches the nostril and the 

 eye ; the portion situated at the lower surface of the snout is slightly concave. All the 

 other shields appear to be narrow, as each shield overlaps a great portion of the shield behind 

 it ; consequently the eye is visible from below the fronto-nasal, this shield covering a large 

 portion of the ocular*. Fronto-nasal with the posterior margin undulated, not extending 

 so far backwards as the rostral. Praeocular situated behind the lower portion of the fronto- 

 nasal, ocular behind its upper portion. A narrow, crescent-shaped supraocular behind each 

 posterior corner of the rostral. There is a subocular plate, nearly as large as the ocular, 

 behind the praeocular, below the ocular and above the two hinder labials. Labials four: 

 the fij'st touches the rostral and nasal, the second the nasal, fronto-nasal and prseocular, the 

 thu'd and fourth the subocular. The frontal and parietal scales scarcely differ from one 

 another in shape and size, and are nearly twice as broad as the scales of the body. 



The body is only a little thicker behind than in front ; its circumference in the middle is 

 contained fourteen times in the total length. The tail is slightly curved, extremely short, its 

 length being equal to (or, in females, less than) the width of the head ; it terminates in a 

 minute spine. Body surrounded by twenty-eight or twenty-nine longitudinal series of scales. 

 I count 500 transverse series (466, Bibr.) ; ten round the tail. 



Light bronze-coloured, each scale on the back lighter in the centre ; below uniform 

 yellowish. 



This species is one of the best-marked Blindworms in India ; we have received specimens 

 from Madras, from the Anamallay Mountains, and from the Deccan. It attains to a length 

 of 16 inches. 



The three views of the head represent it of twice its natural size. 



* This may lead to a misinterpretation of the head-shields, as in the case of Omjchocephalus ivestermanni, 

 where Dr. Liitken takes the fronto-nasal which overlaps the ociUar, for the ocular itself. Bibron very well 

 describes the arrangement of the shields : " La plaque preoculaire, vu son peu de hauteur, ne separe la 

 fronto-nasale et I'oculaire I'une de I'autre, que dans les deux tiers inferieurs de leur etendue verticale." 



2 A 



