Mr. P. R. Lowe on the Crab-Plover. 331 



In respect of the arrangement of the Eustachian tubes and 

 the underlap of the apical portion of the basi-temporal plate, 

 Dromas appears to be larine. Shufeldt says {' Emu/ 

 vol. XV. 1915, p. 6) that in this respect Orthorhamphus is 

 larine, and with this statement I agree, but other Stone- 

 Plover genera such as (Edicnemus seem to present transitions 

 from the pluvialine condition to the larine. Both the Sheath- 

 bills and Hamatopus are in this respect pluvialine, but the 

 condition seen in the former is peculiar. 



The pterygoids in Dromas are somewhat short and pluvia- 

 line. They are compressed from side to side. Viewed from 

 their basal aspect, they appear more ribbon-like than in 

 Larus, in which genus (and other true larine genera) we 

 get an impression of long, thin, and rounded rods. Even 

 in the Laridae, however, the pterygoids are compressed from 

 side to side, and produced dorsally into a thin-edged border. 

 In the Skuas the pterygoids are almost strictly rod-like 

 structures, viewed from every aspect, but they are shorter 

 than in the true Gulls. Although the skulls of Larus canus 

 and Dromas ardeola are almost exactly the same length, and 

 have the same general proportions, yet the length of the 

 pterygoids in Larus are 13'5 mm. as compared to 11 mm. in 

 Dromas. 



In the adult Dromas there is no hint of any articulation 

 between the pterygoid and the basisphenoidal rostrum (no 

 basipterygoid processes). In //«m«/o;?Ms the pterygoids are 

 very short, actually nearly as short as in the Golden Plover. 

 Basipterygoid processes are present, and the whole picture 

 is typically pluvialine. In the Stone-Plovers the pterygoids 

 are neither typically pluvialine, larine, nor stercorarine. 

 Tliey may be said to be oedicneraine. In regard to their 

 length, however, the pterygoids of Orthorhamphus approach 

 a larine condition. Shufeldt (/. c.) says that " the pterygoids 

 of Orthorhamphtis and (Edicnemus are much more like these 

 bones in Gulls, in Chionis, and others, than they are in birds 

 belonging to the typical Charadriinse.^' 



Palatal Region. — The palatal structures of Dromas come 

 closer to those of oedicnemine genera than any other 



