ON THALASSIDKOMA NEREIS. 229 



yellow epidermic layer, which invests a central core of compact fibrous 

 tissue, this in turn being supported by a bony projection developed at the 

 radial side of the first metacarpal. 



As regards the position of the Parridaa in the group Pluviales, it appears 

 to me that they form a well-marked family, with no very obvious relation- 

 ships to any of the other families of that group, approaching, however, 

 perhaps most nearly to the CharadriidaB, from which they are easily 

 distinguishable by the absence of supraorbital glands and occipital 

 foramina, by their enormously elongated toes, by the number of rectrices, 

 and other points. A brief definition of the Parridae may be given as 

 follows : 



Charadriiform birds, with ten rectrices, short caeca, and a tufted oil- 

 gland ; with the ambiens, accessory femoro-caudal, and accessory semi- 

 tendinosus muscles developed, and with the obturator internus triangular ; 

 with a two-notched sternum, and with the digits, including the hallux, 

 greatly developed ; with the skull provided with basipterygoid processes, 

 but lacking occipital foramina and supraorbital gland-impressions. 



40. ON THE PETREL CALLED THALASSIDROMA NEREIS P. z. s. 1881, 

 BY GOULD, AND ITS AFFINITIES.* p ' 735 ' 



IN this Society's Proceedings for the year 1840, the late Mr. Gould 

 described a "beautiful fairy-like " new species of Stormy Petrel from 

 Bass's Straits, which he called Thalassidroma nereis (torn. cit. p. 178), 

 under which name it is figured in the last volume of the * Birds of 

 Australia/ 



Dr. Elliott Coues, in his revision of the family Procellariidaa t, treating 

 of the species under the name Procellaria nereis, says : " I have had the 

 pleasure of examining Mr. Gould's types of this species from Bass's 

 Straits, Australia, now in the collection of the Philadelphia Academy. 

 It is a beautiful little species, quite unlike any other known Stormy 

 Petrel. In form it comes nearer to Procellaria pelagica than to any 

 other species ; and it is probably congeneric with it, though it differs some- 

 what $ in the proportion of the tarsus and toes, and very widely in its 



pattern of coloration The proportions of the tibia and tarsus differ 



from those of pelagica in the greater comparative length of the former." 



* Proc. Zool. Soc. 1881, pp. 735-737. Bead June 21, 1881. 

 t Proceedings of the Academy of Natural Sciences of Philadelphia, 1864, p. 81. 

 The italics are mine. W. A. F. 



