298 PROSAURIA 



CHAP. 



T-shaped interclavicle, while the lateral branches of the latter 

 fuse with the clavicles. The coracoids are broad and entire, 

 still without fenestrae or notches indicative of precoracoids. 

 The parasternum is very elaborate ; it extends from the sternum 

 to the pubic bones, and consists of about twenty-four transverse 

 rows, each of which is composed of a median and two lateral 

 splint-bones. They are irregularly shaped, partly with imbri- 

 cating hooks, and are firmly attached to, in fact still connected 

 with, the deeper portions of -the cutaneous scales of the belly. 

 The three pairs of pelvic bones are fused together at the 

 acetabulum. Pubes and ischia each form one symphysis, and 

 these are connected with each other by partly ossified cartilage 

 and ligaments, so that the originally heart-shaped space is 

 divided, into a pair of ovals. The lateral processes of the pubes 

 are thick, but very short. The ischia have postero- lateral 

 processes. There is also a mostly cartilaginous, unpaired 

 hypo-ischium. 



The fore- and hind-limbs are still primitive in structure ; 

 both pentadactyle. The carpus consists of ten, sometimes eleven 

 pieces, according to the single or double nature of the central 

 element. The proximal series is formed by the radiale, inter- 

 median, and ulnare, with a pisiform. The ulna and radius remain 

 separate. The hurnerus has the usual ectepicondylar in addition 

 to the entepicondylar foramen common to all the Prosauri and 

 Theromorpha. The hind-limbs are typically plantigrade. 



The tail is capable of regeneration, as in many lizards. 



The development of this reptile has recently been studied 

 and described by Howes, 1 who quotes the literature bearing 

 upon -the whole subject. 



A good account of the occurrence and habits of the " Tuatera " 

 has been given by Newman. 2 The Maoris call it " ruatara," 

 " tuatete," or " tuatara," the latter meaning " having spines." 

 Formerly common on the main islands of New Zealand, they are 

 now apparently restricted to some of the islets in the Bay of Plenty, 

 North Island. Bush -fires, wild pigs, dogs and cats, reptile- 

 eating Maori tribes, and the advance of civilisation, have swept 

 them away except on some of the small uninhabited islands,, 

 difficult of access, where they dig burrows, into which they 

 retreat at the slightest sign of danger. They sleep during the- 



1 Trans. Zool. Soc. xv. 2 Trans. N. Zealand Inst. x. 1878, p. 222. 



