of an almost perfect Skeleton of the Plesiosaurus. 419 



removing also the exterior and circular bones from the edges 

 of the paddle as there drawn. I was led to introduce these 

 exterior paddle-bones from the specimen represented, fig. 1, 

 PI. XLII. Geological Transactions, vol. v., in which they are 

 so placed ; but I have subsequently retracted this view, having 

 learnt that when the specimen referred to was found, the bones 

 in question were loose, and had been subsequently glued into 

 their present situation, in consequence of a conjecture of the 

 proprietor. I mention this circumstance lest any real incon- 

 sistency should be supposed to exist between that specimen 

 and the more perfect and illustrative remains now discovered. 

 All the paddles are composed of two rows of nearly circular 

 or discoidal bones, representing the carpus and tarsus, and of 

 five digitated series, representing the metacarpal or metatar- 

 sal and phalangic bones, the distinction between these being 

 inappreciable, though we may of course, in conformity to the 

 usual nomenclature, term the first phalangic bones metacar- 

 pal, &c., if so inclined. The first or anterior digit on each 

 paddle has four phalanges; the last, seven. These are evi- 

 dently complete in the specimen. The whole five digits stand 



as follows : 



Anterior paddle. Posterior paddle. 



1st digit, 4 phalanges. 1st digit, 4 phalanges, 



/and seems 2d ... 8, complete. 

 2d ... "'^complete. 3d ... 10, 1 uncertain whether 

 Sd ... 7, incomplete. 4th ... 9, / complete or not. 



4-th ... 6, incomplete. 5th ... 7, complete. 

 5th ... 7, complete. 

 This great multiplication of joints in the phalangic series 

 strongly distinguishes this animal from all known quadrupeds. 

 In the whole class of mammalia (some cetacea only excepted) 

 the number of phalanges in the perfect and longest digits is 

 restricted to three ; it is the same in most of the reptiles ; but 

 some Saurians, e.g. the crocodile, exceed this number by one 

 joint : birds also have only five phalanges. 



A majority of the cetacea ajjpear to possess only three pha- 

 langes, but in some species the number is increased ; and the 

 Rorqual (a species of Balceua) and the Delpliinm Ddphis pre- 

 sent as many as seven (see Cuvier's Ossemens Fossiles, torn, v., 

 and Camper's Cetacea, PI. 44.), the nearest approximation to 

 the number in the Plesiosaurus, though less than the number 

 in the posterior paddle of that animal by two joints. 



Although all the other analogies of the fossil animal refer it 

 to a class widely difiering from the cetacea, it is yet interest- 

 ing to observe that in these instances, taken from beings of 

 distinct general organization, the use for which nature m- 

 •^ 3 G 2 tended 



