VOL. LXXVI.] PHILOSOPHICAL TRANSACTIONS. 15/ 



cesses, similar to those we find in the vertebrae of the neck in turtles and birds. 

 Not only the 6 posterior but the 5 anterior vertebrae of the back are provided 

 with such processes; of these however Dr. Grew makes no mention. 



Fig. 1 represents the 7th vertebra of the back ; a and c are the ascending and 

 descending processes, forming the articulations with the adjacent vertebrae ; b 

 the transverse process, to which is united the rib fb in b ; de the spinous pro- 

 cess ; HHi the body of the same vertebra. These figures abridged, were all 

 made from the same skeleton, now in the British Museum. The whole 

 length is equal to 12-j- feet, Paris measure; the head equal to 2 feet ; the neck 

 equal to 1 foot ; the trunk equal to 3 feet 8 inches ; the tail equal to 5 feet 8 

 inches. The measurement given by Dr. Grew does not agree with mine ; but 

 he seems not to have taken it with great attention (p. 42), for he makes use of 

 the words about, almost, &c. 



Observation. — What struck me was, the transverse suture, abcfJ'^, which 

 divided the bodies of all the vertebrae of the neck, back, and loins. This 

 division ended with the os sacrum, which was entire, as were also the vertebrae 

 of the tail. Dr. Grew seems only to have taken notice of the sutures belong- 

 ing to the transverse processes. I have a small skeleton of a crocodile equal to 

 13 inches, in which the 7 vertebrae of the neck, 12 of the back, and the 5 of 

 the loins, are divided in the same manner as in the large skeleton in the British 

 Museum. Those of the os sacrum and tail are without, and have no mark of 

 an epiphysis. 



Conclusion. — The transverse division of the vertebrae above-mentioned is also 

 peculiar to this animal ; and there is no epiphysis, as in other animals. To be 

 sure of this, I dissected and made a skeleton of the Lacerta Iguana, Linn. sp. 

 26, perfectly well described by Maregraf, Hist. Bras., p. 236, cap. 1 1 ; but I 

 found no such divisions, though the animal was young, and though it had still 

 epiphyses on the legs, &c. The neck consists of 4 vertebrae, the back of 11, 

 the loins of 9, the os sacrum of 2, as in the crocodile ; the tail of more than 

 60. The dissection of tortoises seemed of consequence, at least a more accu- 

 rate inspection of the vertebrae, particularly those of the neck, as being analo- 

 gous in some respects to those of the crocodile, especially in the structure of 

 the inferior processes d and e, with Im, fig. 1 . 



Fig. 3. Represents 2 vertebrae of the neck of a pretty large turtle, reduced. 

 abbc the bodies ; l and i the ascending, h and t the descending processes ; 

 RK the spinous, abde the transverse, and de the inferior processes, abcdef, the 

 transverse division of these, similar to that in the crocodile. 



Fig. 4, a vertebra from the tail of a young phocaena or porpoise ; in which 

 ab is an orbicular plate, united by means of cartilage to the body of the vertebra 

 ad, which is provided with such a one on both sides, ab and cd. Those bony 



