harddce 



Feb. 12, 1874J 



niscidse A B X + 



ibidajA BX + 



ipid.x B X — 



t A B X Y + 



-jllariida? -^ A B X + 



/ AX + 



iuiid:eA X Y + 



A XY + 



■( XY + 



, , . , ( A X Y — 

 ArdeidEE j v y 



Phalaciocoridss A X + 



Phaethontidx A X Y + 



Fregatidx A + 



Falconida; A + 



StrigidceA — 



Gruid^e A B X Y + 



r-u A -A S A B X Y + 

 CharadnidK j p \- -v- , 



LaridceAX Y + 

 Ale da; A B X — 

 Columbiu A B X Y ± 



NATURE 



J91 



GalbiUidce 



Meropida: A X F — 



\AXY- 

 \AX — 

 Cafinmulgida: A X Y- 

 Skalorniihuice X Y — 

 Comciicl<c A X Y — 

 Momotidu- A X Y— 



Cyi>s,-hJce A — 

 Trochilid.c A — 



< 'n looking at the formula; in the above table it will be 

 .-.cvjii that there is a tendency to similarity in those that 

 are placed in juxtaposition ; and further, that the presence 

 or absence of the ambiens muscle, indicated by the signs 

 + and — , is more constant than the other characters. 

 Thus, among the Ctuulidir, the Picidcc and Ardcida, the 

 ambiens does not vary whilst one or other of the rest is 

 inconstant. There are more reasons than the above for 

 assigning primary importance to the ambiens muscle, 

 which depend on the nature of the tip of the oil-gland 

 and the csca of ihe intestine. For, with but few ex- 

 ceptions, those birds which possess the ambiens muscle 

 have ca;ca to the colon and a tuft of feathers on the oil- 

 gland, whilst those in which the ambiens muscle is absent, 

 have either cteca and a nude oil-gland, or a tufted oil- 

 gland and no cteca. The true relationship of the excep- 

 tions is, however, indicated by other collateral characters, 

 the most important of which is the presence or absence 

 of the accessory femoro-caudal (B) ; that muscle being 

 never found in those birds in which the ambiens is 

 always absent, so that any bird with it developed, is 

 certainly related to those in which the ambiens is present. 

 These facts lead me to propose the division of the class 

 Aves into two primary sub-classes, — the Hoinalogonati^ 

 in vvhich the ambiens is present, and the ^«o;/w/(7 0-0 /M/Zf 

 in which it is always absent. The former of these are 

 printed in the above table in Roman letters, the latter in 

 italics. 



It may be asked, why, on the above principles, are the 

 Ardeidffi and the Strigida; placed with the Homalogona- 

 tous birds, especially as the latter have a nude oil-gland ? 

 The position of the latter of these two families is no doubt 

 r'T-crtain, but the sum of characters is in favour of the 

 s assigned to it. 

 . Lxt, respecting the most important sub-divisions of 

 uie Homalogonatous, and the Anomalogonatous birds. 

 Taking the latter first, because they are fewer in number, 

 and more clearly separable, they are found to fall 

 naturally into three well-detined orders : — (1) those in 

 which the oi'.-gland is nude and the ca;ca of the intestine 

 present ; (2) those in which the oil-gland is tufted and the 

 ciecaare absent ; and (3) those in which the oil gland is 

 nude and the cKca arc absent. These three sections of 

 the Anomalogonatous birds are indicated in Table I. by 

 the corresponding numbers, the Picid^e heading the first, 

 the Passeres the second, and the third comprising the 

 Macrochirts only. To most ornithologists the not un- 

 reasonableness of this arrangement will be fairly 

 apparent. 



• With the knee norm.-il ; that is, with the ambiens crossing it. 

 t With the knee abnormal ; that is, with the ambiens deficient. 



Table II. 

 Class AVES 

 Sub-class HOMALOGONATI 



Order I. GAL LI FORMES 



Coho}-t (a) Struthiones 



Family 1. Struthionida 



Sub-fain. i. Struthioninre 

 „ 2. Rheinas 

 „ 2. CasuariidcB 

 „ 3. Apteryi^ida: 

 „ 4- ? i nail! t da 

 „ (/3) Gallinace^ 



Family i. Palamedeida 

 „ 2. GalliiicE 

 „ 3. Rallida 

 „ 4. Otidida: 



Sub-Jam. I. Otidinse 



„ 2. PheenicopterinEE 

 „ 5. Musotihai^ida 

 „ 6. Ciiculido' 



Siib-faiii. I. Centropina; 

 „ 2. CuculincE 

 „ (-y) PsiTTACI (t) 



Older II. ANSERIFORMES 



Cohort (a) Anseres 



Family i. Anaiida 

 „ 2. Sphcniscidce 

 „ 3. ColymbidcE 

 „ 4. PodicipidcE 

 „ (^) Na.sut^e 



Family i. Procellariidcs 

 „ 2. Fulmaridce 



Sub-Jam. i. Fu'marinae 

 „ 2. Buhveiiinas 



Order III. CICONIIFORMES 

 Cohort (a) Pelargi 

 „ (/3) Catharte.-e 

 „ (y) Herodi.e 

 „ (8) Steganopodes 

 Family i. Pha:thontida: 

 „ 2. Pctecanidcc 

 „ 3. Phalacrocoridce 

 „ 4. Fregatida: 

 „ iy) ACCIPITRES 



Family i. Falconidce 

 „ 2. Strigida 



Order IV. CHARADRIIFORMES 



Cohort (a) COLUMK.E 

 „ (/3) LlMICOL.« 



Family i. Charadriidcc 

 „ 2. Gruida 

 ,, 3. Lariaa 

 „ 4. A lei dec 



Sub-class ANOMALOGONATI 

 Order i. PICIFORMES 



Family i. Picaria: 



Sub-Jam. i. Picidre 



„ 2. Ramphastida: 

 „ 3. Capitor.idse 

 J, 2. Upnpida: 

 „ 3. BucerotidcE 

 „ 4. Alcediniace 



