474 MR. G. A. BOULENGER ON THE [Apr. 19, 



ProGolojyJion'^- , differing, however, in the molar teeth being widei- 

 still, in this i-espect agreeing with Diadectes and Em-jiedias, as 

 figured by Cope t. 



The Vertebral Columx. 



I have very little to add to oui- previovis knowledge of the 

 vertebi'al colunna. Having had gutta-percha and wax impi-essions 

 made of the specimen desci-ibed by Huxley, and also from exam- 

 ination of the type specimen, I can state that intercentra were 

 absent between the doisal vei'tebi-a?, that these were rathei- 

 sti'ongly biconcave, and that ti-ansverse processes did not exist. 

 The number of presacral vei-tebrte in specimen B was twenty. 

 The long and slender pra?sacral ribs were but slightly thickened 

 at the base. 



The length of the tail is still unknown ; but it was probably 

 not much longer than in the type specimen figured by Mantell. 



The Pectoral Arch. 



This was inserted immediately behind the skull, as in the 

 8tegocephala, Pariosaurtis, Procoloplion, and SclerosatorusX, 



Although the fossils at hand do not show the characteristic 

 T-shaped intei-clavicle, I have no doubt the shouldei--gii-dle agi'eed 

 essentially with that of Procolophon. This j)art of the skeleton 

 is best shown by Huxley's specimen. But foi- the antei-ior ex- 

 pansion of the glenoid cavity, which seems to me doubtful, the 

 scapula has left a cast which agrees well with Huxley's i-estoi-ation. 

 But the latter is to a great extent fanciful as regai'ds the coi-acoid, 

 part of which, it is true, is indicated in the figure § by a dotted 

 line. The lai-ge fenesti-a does not appear to have existed, its 

 supposed presence being due to matrix which, I think, could be 

 easily I'emoved were it not that the histoi-ical interest attaching 

 to the specimen precludes its fvirthei- development. The im- 

 portant point, ovei-looked by Huxley, is the pi-esence of a straight 

 transverse suture, extending fi'om the glenoid cavity, which 

 divides the bone into two, the pi'tecoi'acoid and the coi'acoid, the 

 formei- being only a ti-ifle shortei* than the lattei-. Oleithra wei-e 

 certainly not present. 



The Pelvic Arch. 



This has been described veiy shortly by Huxley, and the 

 outline figure given by him indicates a very Lacertilian state of 

 things. I agree with his lepresentation of the ilium, but I am 

 convinced that the supposed impressions of the pubis and ischium 



* Cf. PL XXXI. fig. 3. 



t Proc. Amer. Philos. Soc. xix. 1881, pi. v. 



X The restorations of Scleroscmrus bj' ^oii Huene, Geol. Pal. Abli. x. 1902, p. 29, 

 and of Pariosaurus by Broom, Ann. S. Afr. Mus. iv. 1903, pi. xvi., appear to me both 

 incorrect in representing these reptiles with a distinct neck. Fossils in situ show 

 the clavicular arch to have been under the anteriormost cervical vertebrae. These 

 reptiles had no more neck than a Salamander. 



§ Loc. cii. p. 78. 



