Mr. W. K. Parker on Pterocles, Syrrhaptes, and Tinamus. 305 



gether out of his mind when considering such birds as those we are 

 speaking of : at any rate, dogmatism on either side, on a subject so 

 far beyond the reach of our feeble faculties and limited knowledge, 

 has in it something of profanity. I have, up to this time, only been 

 able to get a sight of the skeletons of Pterocles arenarius (see Osteol. 

 Cat. Mus. Coll. Chir. vol. i. p. 2/3, No. 1421), of Hemipodius varius 

 (ibid. p. 274, No. 1423), of a specimen of an undetermined species 

 of Hemipodius (which died soon after its arrival at the Gardens, and 

 was lent to me by Mr. Gerrard), and of a Syrrhaptes paradoxus 

 and a Tinamus robustus, for which I am indebted to the Council of 

 this Society. 



" I shall now merely indicate the curious composition, so to speak, 

 of these birds, and begin with that of the Sand-Grouse. 



" These beautiful and gentle birds are seen at once to have in them 

 something both of the Ptarmigan and the Pigeon ; but there is in 

 their physiognomy a marked inferiority of expression, quite in con- 

 trast with the sharp, intelligent look of the typical Fowls, and very 

 much below what we see in the Pigeon-tribe. 



" This is exactly in harmony with what the skeleton reveals ; for 

 whilst the characters of both these types are almost inextricably 

 interwoven, yet there is in many points a marked inferiority of cha- 

 racter — a less degree of elevation above the Struthious style of struc- 

 ture. What there is of the Bustard (Otis) in them (which Pro- 

 fessor Owen, 'Osteol. Catal.' p. 274, points out) is only part of their 

 general relationship to the Pluvialine type. 



" It is in those parts of the skull and face which are first mapped 

 out in thickened blastema, and then differentiated into clear cartilage, 

 at some considerable period of the early embryonic life anterior to 

 the deposit of bone, that we find the most instructive modifications 

 of structure. 



" I allude especially to the basis cranii and to the upper part of 

 the first facial arch, that is, to the occipital and sphenoidal regions, 

 and to the pterygoids, palatine bones, and vomer. Not only do these 

 bones (with the exception of the vomer, which is absent as in the 

 Pigeons) show a marked * struthious ' inferiority in the Syrrhaptes 

 (the culmination of the Pterocline type of structure) , but the ster- 

 num, which literally unites that of the Ptarmigan with its counter- 

 part in the Pigeon, is inferior in one important point, not only to 

 this, but also to that of the whole Pluvialine group. 



" The heel, which is a mere rudiment in Pterocles proper, is ab- 

 sent in the Syrrhaptes ; and the whole pelvic extremity is almost the 

 counterpart of that of the Swifts (Cypselus) in deficient growth. I 

 believe that it would take a very clever anatomist to detect any differ- 

 ence between the wing-bones of the * Pteroclirue' and those of a 

 typical Pigeon. 



" The elongated feathers of the tail and wings of Syrrhaptes give 

 it one of its peculiarities of character : the two middle tail-feathers 

 have already become elongated in Pterocles setarius (the Pin-tailed 

 Sand-Grouse of Temminck), its nearest ally. 



" I cannot conclude this rough outline of what I wish to say about 



