198 PROCEEDINGS OP THE ACADEMY OF 



conceive of it as presenting irregular saliencies drawn out even into arm-like 

 processes, reaching toward, or touching, mammalian, reptilian and piscine 

 groups ; or reentrances, into which are extended corresponding-outgrowths from 

 other forms of life. Classification is not the laying side by side of plane 

 figures, circular or otherwise ; but the piling over against each other of 

 variously shaped solids, that meet and fit at mutually conformed and adapted 

 points or surfaces of contact. The bird is laid against the mammal' at the 

 point Slrulhio ; against the reptile at the point Archfeopte7-i,z, or rather by a 

 surface of which this type was one point; against the fish (probably the Elas- 

 mobranchiate fish) at the point Sjj/ieniscus, and so on. Inside the figure Aves, 

 everywhere from centre to superficies, lie piled in certain order, all lesser 

 figures, from species to sub-class, mutually fitting on every side. The problem 

 is to discover, as nearly as may be, the plan according to which the several 

 stones are shapen, coaptated in the building of the solid structure. We do 

 not deal with an empty shell.* 



Professor Huxley's classificationf is materially difl^erent from any other. It is 

 probably the most stirring ornitholgical event since the discovery of Archceop- 

 teryx. It is an attempt to classif}^ birds with reference to a single set of charac- 

 ters — the modifications of certain cranial bones. The test is critically applied 

 and rigidly carried out, necessitating a new division of the class, bj' breaking 

 up most of the higher groups usually recognized, substititting others, and call- 

 ing for a hitherto unsuspected sequence of orders and families. The primary 

 division is into three " orders," apparently correspondent in taxonomic value 

 with the "sub-classes" of most writers. Saururx, represented by the Archm- 

 opteryx alone : Ratitse, including Struthiones et afif., seemingly about equivalent 

 to Plniysteriue Nitz., Brevipenne.s Lillj., Cursores s. Curretitcs alior.; and C'arinatie, 

 embracing all other existing birds, that agree in the possession of a keeled 

 sternum. This initial step, however, is taken upon other grounds than the 

 characters of the palatal, &c., bones alone ; and its adoption may be found 

 imperative. I am not prepared to otter anything upon the question, Carinaiie 

 only falling within the scope of the present paper. These are divided into four 

 orders, correspondently with as many main modifications of the bony palate, 

 that only exceptionally merge into each other. Dicholophus, Crax (^ylobicera) 

 and Picidie are the only intermediate forms known to the author. The two 

 first may be regarded " as transitional between the Schizognathous and 

 Desmognathous sections, or, at any rate, as approaching the latter division" 

 (1. c, p. 455). The woodpeckers " are in fact not Desmognathous, the palate 

 in these birds exhibiting rather a degradation and simplification of. the 

 Aegithognathous structure," (p. 468.) The fact then is unquestionable, that 

 C'arinatie may be divided into four groups by certain characters, the value of 

 which, as affording correct indications of natural affinities or not, is the point 

 at issue. 



It will scarcely be questioned hj any, that groups, to be taxonomically 

 equivalent, should be separated from each other by characters of equal or 

 corresponding value ; that is, the sum total or average of distinctive features 

 should be as nearly as possible of the same amount or degree. An inequality 

 in this respect of the groups formed under this system is evident. Not to refer 

 to the primary divisions, in the next lower scale, that of " sub-orders," one 

 family stands apart from all other Carinatie — the Tinamous alone representing 

 Drovieeognathoi. As the author ivnlj says, " the small actual extent of the group 

 in which " the dromaiognathous structure obtains, is no argument against 

 its validity as a sub-order. While this would be conceded, issue would be 



* The three foregoing paragraphs are allowed to stand as they were written, with some 

 misgivings; not lest the thoughts that prompted them be not well enough, but lest the 

 expressions used may fail to convey to others exactly the idea desired to be advanced. I 

 do not expect to be lipre accused of using the imaginative in place of the reasoning facul- 

 ties, unless I am misunderstood. 



t P. Z. S., 18G7, p. 415. 



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