Newman. — Notes on the Fhysiology and Anatomy of the Tuatara. 231 



At the under surface of the jaw are small white scales, some partially 

 others fully formed ; they partially overlap each other, as do shingles on a 

 house roof. At the throat they are more largely and fully developed, and 

 are of irregular shape, usually with many straight sides and rounded edges. 

 Gradually these scales hecome arranged in parallel rows, the posterior edge 

 of the front row overlapping the anterior edges of back ridge. On the 

 abdomen these plates are much larger and more regtilar in shape (parallelo- 

 grams) and are arranged in rows, each row being closely bound by its 

 anterior edge to an abdominal rib. About an inch from the transverse vent 

 they become smaller, more irregular in shape, and the ends of the rows bend 

 round, so that at the vent the rows are indistinct. Behind the vent they are 

 small, but soon grow larger, and then rows of straight- sided plates almost 

 encircle the tail. These tail plates are longer and narrower, though as 

 regularly placed as those on the abdomen. Under thelihroat the skin hangs 

 in loose irregular folds. 



No sign of ears. Nostrils, two small holes almost hidden by lateral 

 cranial skin ridges. These holes look upwards. A needle passed into them 

 passes downwards and forwards — not backwards. 

 Mouth 1-2 inches long, quite straight. 



Fore hmbs shorter than the hind ones. Pes and manus have each five 

 digits armed with sharp nails, curved like the teeth of a rodent. Pollux 

 short and thick. HaUux slender and widely se^Darated from other digits. 

 Both pes and manus are large and covered on the under surface with small 

 white scales. 



To the exhaustive description of the abdomhial ribs given by Giinther I 

 cannot add anything, except a remark on a peculiarity which he noticed in 

 one specimen. He examined six specimens and in one he found " a very 

 curious anomaly as regards the union of the three bones of which the 

 abdominal ribs consist ; they loere united by joints." This peculiarity existed 

 only in the alternate ribs. This did not obtain in either of my specimens, 

 which belonged to a different species. It is therefore probably a variation, 

 and not a mark of a distinct species. 



Deiititioji. 

 Dr. Giinther described specimens in all of which there were in each 

 premaxillary bone a pair of incisors, far larger than any of the other teeth. 

 These teeth were confluent at the base, and in old specimens when the cones 

 were worn down, the incisor appeared as if a single tooth, resembling a ro- 

 dent's incisor. Dr. Knox, however, found that in one of his two specimens 

 there were in each premaxilla three teeth, all confluent at the base; the other 

 specimen had but two cones. This newly discovered cone is nearer the 

 middle line than the others. It is far smaller, slenderer, and sharper, and 



