Hector. — On the Fossil RejJtilia of Neiv Zealand. 341 



dimensions: — Antero-posteriov length 2-7 inches, transverse diameter 3 '2 inches, 

 vertical 2'8 inches, diameter of neural canal "75 inch. 



No, 1 c. — To this same species Dr. Haast has referred a fine specimen, 

 which is exhibited in the Canterbury Museum, obtained at Boby's Creek, at 

 Waipara. It is only partially woi-ked out from the matrix, but shows the 

 ventral aspect of the greater part of the trunk and tail of a Plesiosaur that 

 measui'ed probably 10 feet in length, the distance between the anterior 

 margin of the thorax and the pubic arch being 4 feet. The portions of the 

 skeleton which are visible are thirty-five vertebrae belonging to the dorsal and 

 caudal regions, the scapula and pelvic arches, with appendages, and both 

 vertebral and abdominal ribs. The transverse diameter of the vertebral centra 

 is 2-15 inches, being greater than the vertical, while the length is only 1 -7 inches. 

 The height of the neural spines and the length of the transverse processes is 

 about equal to the height of the vertebral centrum in the middle part of the 

 back. The caudal vertebrae diminish rapidly in diameter and length towards 

 the extremity of the taU. The coracoids form a very wide, compressed, bony 

 plate, not much longer than the width in the middle, but constricted posteriorly, 

 their length being equal to about six thoracic vertebrae. The ribs are slightly 

 compressed, and do not agree well with Professor Owen's description of the 

 type of the species to which this has been referred. The form of the vertebral 

 centrum also exhibits so marked a difierence in the proportion of the transverse 

 diameter to the length, as to lead to the belief that it must have been a very 

 difierent animal ; but until it has been more clearly worked out from the 

 matrix this cannot be well decided. 



2. Plesiosaurus ckassicostatus, Owen. Geol. Mag., 1870, p. 52. 



No. 2 a. — This fine slab, collected by Mr. R. L. Holmes at Boby's Creek, 

 Waipara, exhibits the left side of the thorax and neck of a well-grown animal. 

 A fullsized drawing of the specimen sent to Professor Owen enabled him to name 

 this species ; but, as the bones have since been more completely worked out 

 from the matrix, and three dorsal centra discovered and extracted from beneath 

 the ribs, I am able to add some further particulars regarding this interesting 

 specimen. 



Professor Owen remai'ks : — " Whoever may glance at a specimen or figure 

 of a similarly-preserved trunk of a Plesiosaurus will appreciate the generic 

 character of the ribs in the New Zealand fossil. They are robust, subcircular 

 in section, exjjanding somewhat, or thickening, at their middle, obliterating 

 thei'e or leaving very little of intercostal space, at least in the collapsed 

 condition of the chest. They are likewise solid." 



The portion of the*Qeck which has been preserved consists of seven cervical 

 centra, each 1 -4 inches in length, with 2 '5 inches transverse, and 1 -3 inches vertical 



