﻿254 [Ko. 4, 



Ojf THE OCCUEEENCE OF A SUPEEOREITAL CHAIN OF Boi^ES IN" THE Ar- 



boeicol."e(Wood-paeteidges). — ^y James Wood-Mason of Queen's 

 College, Oxford. 



(Eeceived April 20th ; read March 4th, 1874.) 

 (WithPkte II). 

 In his elaborate paper * On the Osteology of the Gallinaceous Birds and 

 Tinamous' read before the Linnean Society on November 25th, 1862, 

 Professor W. Kitchen Parker announced the remarkable discovery, in 

 Tinamus rohustus, " of a v^^hole row of super-orbital bones, the like of 

 which must be sought for, not amongst birds, but in a group of creatui-es a 

 long way down in the scale," viz., in the Skinks and Blind-worms. Further 

 on in the same paper, the presence of a similar chain of superorbitals in 

 Psopliia crepita7is, "only in an enfeebled form," is mentioned. The same 

 author, in a memoir ' On the Structure and Development of the Skull in the 

 Ostrich Tribe' read before the Royal Society on March 9th, 1865, records 

 the occurrence of a double row of these bones extending all along the 

 superorbital margin from the lacrymal to the post-frontal process in Tinamus 

 variegatus. 



I have now to announce the occurrence of a similar chain of ossicles in 

 four out of the eight recognized species of Arhoricola, a genus of Indian 

 Partridges, viz., in A. torqueola, atrogularis, rufogularis, and intermedia ; 

 and I look forward with especial interest to the examination of skulls of 

 the two of the remaining species which have been referred by some authors 

 to the subgenus Feloperdioc^ and which inhabit the Tenasserim provinces 

 and the Malay peninsula. 



Mr. Parker has pointed out how in the Lapwing (Vanellas) the fron- 

 tal in the young bird sends out square denticles of bony substance under 

 and beyond the nasal gland, which coalesce with one another, with the 

 lachrymal in front, and with post-frontal process behind, so as to form 

 beyond the gland a secondary frontal margin, which acts as a smooth eave 

 to the eyeball ; and that the superorbital chain of bones in the Tinamou 

 takes the place of this secondary frontal margin and the denticles in the Lap- 

 wing, the same end being attained by different means. But in the Arbori- 

 colas the arrangement is totally different : in them the margins of the com- 

 bined frontals so far from being bevelled or scooped for the reception of the 

 nasal gland are rather prominent and the internal edges of tlie ossicles 

 composing the chain come into close relation of apposition with them. 



I have examined a considerable number of species of Gallinaceous birds, 

 small and great, including, by the kindness of my friend Major Godwin- 

 Austen, a species of Bauihusicola, but have hitherto failed to detect so much 

 as a single grain of bone in the superorbital membrane of any one of them. 



