182 OPHIDIA. 



FAMILY OF ROUGU-TAIL^—UBOPELTID^. 



Body cylindrical, with a short, narrow head not distinct from neck ; tail 

 extremely short, truncated or scarcely tapering, generally terminating* in a 

 rough, naked disk, or covered with keeled scales (see Melanopliidiuiii). The 

 body is covered with rounded, polished, imbricate scales, those in the 

 ventral series being always somewhat larger than the rest. Only one pair 

 of frontals ; four upper labials. Eye very small. Cleft of the mouth of 

 moderate width ; teeth in small number, small, subequal in size, in the 

 maxillary and mandibulary bones, none on the palate. There is no longi- 

 tudinal fold at the chin, except in Melanophidium. No rudiments of hinder 

 extremities. 



This family, founded by J. Miiller, contains forms which, from the simplicity of the 

 shields of their head, from theii- scales, their short tail, and their but little dilatable mouth, 

 bear some resemblance to the Typhlopidce. They also, like the Typhlopes, live under 

 ground, — theii- conical head, followed by a generally very stout neck, their rigid body, and, 

 above all, their short, strong, and posteriorly shielded tail being admirably adapted for 

 bun-owing. The species are very similar to one another, so that a general description will 

 suffice for all. 



The head is always narrower than the neck, which is generally slightly swollen and the 

 thickest part of the trunk. Very frequently the longitudinal axis of the head is not the same 

 as that of the neck, the head being impressed on one side, as if it had been dislocated 

 during some eifort of the snake to penetrate the soil. The rostral shield is conical, frequently 

 pointed, and sometimes (Bhinojphis) extending backwards to the frontals, entirely separating 

 the nasals from each other. The nasal is large, pierced inferiorly by a nostril which is 

 situated on the side of the head ; the nasal is in contact with the first and second labials. 

 Only one pair of frontals, in contact Avith second and third labials ; a six-sided vertical, the 

 lateral margins of which are sometimes extremely short ; a pair of well-developed occipitals, 

 in contact with the fourth labial. The eye is very small, and covered by a separate shield 

 in Plectrurus only, where also a supraorbital and postocular can be distinguished, the eye 

 resting on the third labial ; in the other species these shields are confluent, forming an ocular, 

 the eye being visible from behind a transparent portion of the ocular. The labials increase 

 in size backwards, the last forming a broad suture with the occipital. 



The scales are short, rounded, polished, without apical groove, rather larger in the ventral 

 series than in the dorsal; a series of narrow ventral shields* becomes distinct at a short 

 distance behind tlie throat ; the vent is covered by a bifid anal. The subcaudals are scale- 



* In counting the ventral shields I have always commenced from the first scale behind the mental shield. 



