244 Mr. Brayley on the Distribution in the Animal Kingdom 



Among Fishes, in which we approach the first sensible ter- 

 mination of the function of animal heat, on advancing towards 

 the passage from the vertebrated to the invertebrated animals 

 by means of the intermediate group of Annelida, we first ob- 

 serve among the Vertebrata a decided tendency to the pro- 

 duction or development of animal light; without, however, that 

 power being actually attained until we come to the Annelida 

 themselves, constituting the next group: — the proofs of these 

 facts requiring much explanation and discussion, are neces- 

 sarily reserved for the Memoir itself. Corresponding pha^no- 

 mena are observable among the Coleopterous insects forming 

 part of the Annulosa. 



These facts indicate that the extreme terms of the animal- 

 heat series, including (so far as our present knowledge extends,) 

 Birds, Mammalia, and certain Fishes, — and those of the ani- 

 mat-light series, including genera or species belonging to every 

 great group of Invertebrata, and to two, at least, of the inter- 

 mediate or osculant groups (viz. Annulosa, Radiata, Acrita, 

 and Mollusca; — Annelida and Tunicata) — the terms of ap- 

 parent evanescence of each power — are connected together by 

 a gradual transition and exchange of functions. Thus the ge- 

 neral result to which these facts lead is, that, regarding the 

 entire animal kingdom, we may observe, — commencing with 

 the maximum point of animal heat, — a gradual diminution of 

 the power of producing it, while the power of producing ani- 

 mal light, or at least a tendency towards it, as gradually takes 

 its place, rises to its own maximum, and in its turn gradually 

 diminishes and is reciprocally replaced by the power of pro- 

 no explanation; those designated Annelida, Annulosa, Arachnida, Crus- 

 tacea, Cirripeda, and Cephalopoda, are also substantially the same with 

 those of other naturalists. 



The Reptilia of Macleay include those of Brongniart and Cuvier, with 

 the exception of the Batraciens, which constitute Macleay's Amphibia. 

 The Ametabola include those of Leach, and, generally, all those Annulosa 

 which, "constructed on the same plan with the larvae of true insects," "are 

 rendered incapable by Nature of completing their metamorphosis, and are 

 able to perform the offices of adult life in all the various stages of an in- 

 complete change of form. {Ho7\ Enfomol., p. 287.) The Mandibulata and 

 Haustellata are those of Clairville, being the Insectes Broyeurs and Insectes 

 Suceiirs, res-pectively, of several of the French naturalists. The Acrita 

 comprise, under the name of Intestina, such of the Intestinaux of Cuvier 

 as form the greatest part of his second and third divisions o^ Intestinaiix 

 paretichymateuxy and of the Vers mollasscs of Lamarck ; the Polypi na- 

 tauten J the Polypi 'vaginaii of J^amarck ; the Polypi riidcs ; and the Aga^ 

 straires of Blamville. The Tunicata are the Tuniciers of Lamarck, the 

 Acephales sans Coquilles of Cuvier. The Mollusca agree with those of 

 Cuvier, excluding the order last named, together with the Cephalopodes and 

 the Cirrhojwdcs, which, like the Tunicata, are formed into distinct osculant 

 groups. 



