De la BECHE and CONYBEARE, 1821

560	Mr. De la BECHE and Mr. CONYBEARE on
the head of this paper. The numerous important and illustrative specimens which he placed at my disposal, proved of material aid, and still more so his general acquaintance with the subject, of which I subsequently enjoyed the fullest advantage ; so that the facts now submitted to the Society must be considered as the fruit of inquiries prosecuted by us in common. A skeleton of the animal in question, deficient only in the bones of the head, preserved in the well known collection of Col. Birch, (who most liberally allowed us the full use of the very valuable materials he possessed)* confirmed in a most satisfactory manner most of my previous conjectures, and enabled us to assign to it its true place in the zoological order, and to designate it by an appropriate name. That of Plesiosaurus has been chosen, as expressing its near approach to the order Lacerta. The points of analogy between the newly discovered animal and the Ichthyosaurus are sufficiently numerous and important to evince the propriety of their being referred to the same great natural family, a family on every account highly deserving an attentive examination, its members being not only unknown in the recent state, but presenting many peculiarities of general structure, of which no other examples had been previously observed ; and of that most interesting description which affords intermediate forms, and as it were a transition between different races, and adds new links to the connected chain of organized beings. †<
* I have also to acknowledge our obligations on -similar grounds to Mr. Bright, Dr. Dyer, Messrs. Miller, Johnson, Braikenridge, Cumberland, and Page of Bristol. † When alluding to the regular gradation, and, as it were, the linked and concatenated series of animal forms, we would wish carefully to guard against the absurd and extravagant application which has sometimes been made of this notion. In the original formation of animated beings, the plan evidently to be traced throughout is this. That every place capable of supporting animal life should be so filled, and that every possible mode of sustenance should be taken advantage of; hence every possible variety of structure became necessary, many of them such as to involve a total change of parts, but others again, such as required nothing beyond a modification of similar parts, slight indeed in external appearance, yet important in subserving the peculiar habits and economy of the different animals ; in these cases the unity of general design was preserved, while the requisite peculiarity of organisation was superinduced ; nor can there be anywhere found a more striking proof of the infinite riches of creative design, or of the infinite wisdom which guided their application. Some physiologists however (and Lamarck is more especially censurable on this account) have most ridiculously imagined that the links hence arising represent real transitions from one branch to another of the animal kingdom ; that through a series of such links, and by means of the constant tendency of the vital fluids, urged by animal appetencies to perfect old organs and develop new ones, that which was once a polypus became successively a mollusca, a fish, a quadruped ; an idea so monstrous, and so completely at variance with the structure of the peculiar organs considered in the detail (which is in the great majority of instances such that no conceivable appetency could have any conceivable tendency to produce it) and no less so with the evident permanency of all animal forms, that nothing less than the credulity of a material philosophy could have been brought for a single moment to entertain it-nothing less than its bigotry to defend it.