346 Transactions. — Geology. 



the proximal end is slightly expanded, 2-5 inches in diameter, and presents 

 two distinct regularly convex articular surfaces. The distal extremity is 

 compressed, but, unlike Plesiosaurus, the com[)ression is at right angles to the 

 greatest diameter of the other end of the bone, and is 4-5 inches in diameter, 

 V)y 1 inch in width. The vertebral centrum is circular, with two very distinct 

 inferior foramina. There are four articular facets, two on the upper and two 

 on the lower quadrants, for the neural arch and the costal processes respectively. 

 The articular surfaces of the centi'um are deeply excavated and concentrically 

 striated, but with a well-marked central elevation and pit. The diameter of 

 the centrum is 1 -9 inches, its length 1 -2 inches, and the thickness between the 

 conical excavations of the articular fiicets is -7 inch. 



ISTo. 7 b. — This specimen is associated witli the above on account of the 

 double facet on the proximal end of the humerus, which is 10 inches long. 

 The vertebrae included in this slab are proportionately larger but not so concave 

 as in the type. They are ft-om the posterior dorsal region, and measure 

 2 "5 inches in length by 3 inches in diameter. 



No. 7 c. — The occurrence of a vertebral centrum, having the character of 

 this species, connects with it provisionally a fragment of a pelvic arch 

 contained in another slab. It consists of a hatchet-shaped pubic bone of the 

 right side, articulated to a portion of the corresponding bone of the left side 

 by a symphysis 4 inches long. Where these bones unite they are thickened 

 so as to form a wide triang:ular surface of attachment. 



8. Mauisaurus haastii, n. 



sp. 



The Sauropterygians referred to this genus are easily distinguished from 

 Plesiosatirus by the character of the corncoid and the elongated vertebra?. 

 In the latter respect it approaches the genus Elasynosaurus of Cope, but 

 differs from it in the scapular arch, and particidar-ly in the powerful muscular 

 attachments evidenced by the humerus. 



The huge reptilian distinguished by the above name is only represented in 

 the collection by vertebrae, paddle bones, and coracoids, and a few rib fragments, 

 of at least three individuals, obtained from the Cheviot Hills and the Amuri 

 Bluff. No skull fragments or teeth have been found which can be referred to 

 this animal, unless it be three teeth and a matrix cast of a portion of the jaw 

 of a specimen (8 h) obtained at Boby's Creek, Waipara, by Mr W. T. L. 

 Travers, and which is reported to be a fragment of the same block that was lost 

 in the Matoaka, that contained the fine jaws and teeth described by Dr Haast.* 



One of these teeth has been figui-ecl (PI. XXIV., G- a, h, c). It has a 

 compressed, conical, slightljr curved form ; the crown is of dense black enamel, 

 with a slightly swollen ferruginous base that is oblicpiely truncate and 



* Haast, Trans. N.Z. Inst., II., 186. 



