444 

 ANALYSIS OF GENERA. 



. Shell ribbed, 

 Operculum l rta J^ U8 \ Ekphantulum. 



f more or less Caecum She » ™S ed . 



J Anellum. 



("Growth I concave - ' Shell smooth, 



Shell succes- } orbicular! Fartulum. 



JSf 38**1 V™"™ _ K . 



— qJ convex Brochina. 



SO | ^Growth 



^fij] spiral Meioceras. 



O Shell persis- 

 tent Strebloceras. 



4. Description of Riama, a New Genus of Lizards, form- 

 ing a distinct Family. By Dr. John Edward Gray, 

 F.R.S., F.L.S., V.P.Z.S., Pres. Ent. Soc. etc. 



(Reptilia, PI. XV.) 



Mr. Louis Fraser has lately sent to the British Museum a con- 

 siderable series of Lizards, Snakes, and Toads and Frogs from Gua- 

 yaquil, in spirits. Among other interesting species is an annulated 

 Lizard, which, as it cannot be referred to any of the existing families, 

 and has a very peculiar external appearauce, must at the same time 

 be considered as the type of a new genus and new family. 



This Lizard belongs to the section of Cyclosaurce, which have a 

 distinct longitudinal fold along each side like the Zonuridce ; but it 

 differs from the animal of that family in all the scales of the body 

 and tail being elongate, four-sided, placed in transverse rings and 

 regular longitudinal series, like the scales of the A?nphisbcenidce, while 

 the scales of the back and tail of the Zonuridce are all rhombic and 

 more or less distinctly keeled. It differs from the Amphisbcenidce in 

 having an elongated head, four distinct moderately strong limbs 

 (each furnished with five toes armed with claws), and broad square 

 shields on the central part of the belly and tail. 



It differs from the genera of the Chalcidce in the position of the 

 nostril (which in the genera of this family is large and placed in the 

 suture between the lower edge of the nasal and the upper edge of the 

 labial shield), and in the presence of exposed ears, which in that fa- 

 mily are entirely hidden under the skin. 



These animals have the general form of the Lizards — their elon- 

 gated head furnished with regular shields, well developed eyes co- 

 vered with eyelids, well developed legs and feet, and a bifid tongue 

 with acute lobes, combined with small regular square or rather elon- 

 gated four-sided scales forming rings round the body. The scales of 

 the different rings are arranged in regular longitudinal series, smooth, 

 impressed, not imbricate one over the other, but like those of Am- 

 phisbcena : indeed on looking at its back it might be almost taken for 



