60 



VERTEBRATA. 



No. 222. Ichthyosaurus tenuirostris, Conyb. 



Head and Neck. This specimen, from the Lias in Boll, Wirtemberg, is 

 in the Cabinet of Dr. Gunther, Dresden. Size, 18 x 8. Price, $2.50. 



No. 223. Ichthyosaurus tenuriostris, Conyb. 



Paddle and Scapula. This beautiful fossil, figured by Cuvier, is from the 

 Lias at Lyme-Regis, England, and is preserved in the Garden of Plants. 



Size, 10 x 6. Price, $3.00. 



No. 224. Ichthyosaurus . 



Vertebra. The original, from the Lias at Lyme-Regis, England, is in the 

 Ward Museum in the University of Rochester. Price, $0.50. 



No. 225. Plesiosaurus dolichodeirus, Conyb. 



Skeleton on slab. The Plesiosaurus was first discovered in 1823, by Cony- 

 beare and De la Beche. Cuvier thought " its structure the most singular and its 

 characters the most anomalous that had been found amid the ruins of a former 

 world." " To the head of a Lizard (wrote Buckland) it united the teeth of a 

 Crocodile, a neck of enormous length, resembling the body of a Serpent, a trunk 

 and tail having the proportions of an ordinary quadruped, the ribs of a Chame- 

 leon, and the paddles of a Whale." The skull is three times longer than its 

 breadth, and subcompressed. The cranium is quadrate ; nostrils small and situ- 

 ated near the eye ; teeth slightly recurved, striated, sharp, long, and slender, 

 lodged in distinct alveoli, — the anterior being the longest. The swan-like neck 

 consists of from twenty to forty vertebrae, while living Reptiles have not over 

 nine cervicals. The pectoral arch is remarkable for the greatly elongated and 

 broad coracoid bones. The clavicle is united to the scapula as in Chelonia. Next 

 to Turtles, the P. exhibits the greatest development of abdominal ribs. The ribs 

 are articulated as in Lizards. The digits of the fore-paddle support respectively 

 3, 5-7, 8 or 9, 8, and 5 or 6, phalanges ; those of the hind-paddle have 3, 5, 8 or 9, 

 8, and 6. The P. differs from the Ichthyosaurus in being pentadactylous, in hav- 

 ing a long neck, longer and more flexible paddles, a shorter tail, vertebras longer 

 and nearly flat with two pits on the under-side, and more slender teeth. The lat- 



