196 MR. A. H. GARROD ON THE [Fcb. 1, 



forward to become part of the broad thin tendon which covers the 

 knee and is inserted in the front of the tibia-head, the patella being 

 situated in it, together with the long, slender, and flat tendon of the 

 ambiens muscle, which is situated below it, running obliquely from 

 inside and above, outwards and downwards. In many birds this 

 muscle does not extend below the level of the femur, but ends 

 inferiorly by blending with the vastus externus ; and consequently, 

 where such is the case, it evidently cannot, as it does otherwise, 

 cover any of the flexors of the leg." Whether this postacetabular 

 portion of the tensor fascice is present or absent can be found by 

 referring to the Table (p. 199). There are not many birds in which 

 it is very small. 



As the Anserine affinities of the Screamers are being discussed, it 

 ought to be mentioned that in all the former the great pectoral 

 flexor of the wing is peculiarly elongate, and extends upwards above 

 the syynjihysis fiircidce, with its fellow forming a median raphe as an 

 anterior continuation of the carina ster7ii. The only other birds in 

 which this occurs are the Penguins. In the Screamers the great 

 pectoral flexor is not large, and does not extend upwards above the 

 middle of the furcula. 



In the Anseres the extensor pectoral (second pectoral) is always 

 very long and broad, reaching the lower end of the sternum. In 

 Chauna it does not extend nearly to the posterior margin of the 

 sternum, and it is not bulky. 



Again, the muscles of the Anseres are always intensely dark in 

 colour, whilst in the Screamer they are quite pale. In this respect 

 the two groups differ in the same way as do the Seals and the 

 Sirenia among Mammals. 



Osseous System. — The skull, being that portion of the skeleton 

 which is least permeated with air, will receive the greatest attention 

 on the present occasion. With reference to it Prof. Parker remarks*, 

 " All the skull and face, except at its two ends, conforms to the 

 lamellirostral type." Prof. Huxley also places Palamedea in his 

 group " dienomorphse," among the several features characterizing 

 those birds being that " the lachrymal region of the skull is remark- 

 ably long." That such is not the case in Chauna, Prof. Parker has 

 remarked in his article " Birds " in the Encyclopaedia Britannicaf. 



It may be well before proceeding further to inquire more fully 

 into the nature of the lamellirostral type. Prof. Parker tells us that 

 " the great embryological distinctions between the skull and face of 

 the Geese and Fowls are, first, that in the latter the space between 

 the periotic mass and the superoccipital cartilage is a mere chink, in 

 the latter a persistent oval space ; and secondly, that the anterior 

 parts of the face, viz. the prsemaxillse, prsevomers [maxillse], and 

 dentaries are small and compressed in the Fowls, large and out- 

 spread in the sifting birds." A glance at the accompanying figures 

 of the posterior surface of the skulls of a Magellanic Goose, a Derbian 

 Screamer, and a Razor-billed Curassow will enable the reader to decide 

 for himself which of the two groups, the Anseres or the Gallinae, the 



* P. Z. S. 18r>3, p. .514. t Enc. Brit. 8tli prlit. vol, iii. p. 712. 



