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Show 1881.] MR. W. A. FORBES ON THALASSIDROMA NEREIS. 735 1. O n the Petrel called Thalassidroma nereis by Gould, and its Affinities. By W . A. F O R B E S , B.A., F.L.S., F.G.S., Prosector to the Zoological Society. [Received May 17, 1881.] 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 Procellariidse1, 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 somewhat2 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." Amongst the Petrels mentioned at various times by the late Prof. Garrod as having been examined by him, a species several times occurs which is doubtfully named "Procellaria (or Thalassidroma)fregataV* The specimens dissected by him are now before me, and have been identified by Mr. Salvin as being really referable to the Procellaria nereis of Gould, an example of which, from the Falkland Islands, is now in the museum of Messrs. Salvin and Godman. A careful examination of the three spirit-specimens of this bird, as well as of the skin mentioned, have convinced me that this species is not referable to the true genus Procellaria as represented by Procellaria pelagica, and is in fact in no way related to that group of Petrels, but has its nearest allies in the flat-clawed genera Oceanites, Fregetta, and Pelagodroma. In his paper on the muscles of the thigh in Birds4 the late Prof. Garrod divided the Nasutse, or Petrels, into two groups, the "Storm-Petrels" and the Fulmaridee, the former group differing from the latter in that they possess the accessory semitendinosus muscle (Y), but lack intestinal caeca. In the Fulmaridae, on the other hand, the accessory semitendinosus muscle is absent, but cseca are present. The species of Storm-Petrels on which this generalization was based are called, with doubt5," Procellaria pelagica and P.fregata," the latter being the species now identified by Mr. Salvin 1 Proceedings of the Academy of Natural Sciences of Philadelphia, 1864, p. 81. 2 Tbe italics are mine.-W. A. F. 3 Cf. P. Z. S. 1873, pp. 470 and 641. • P. Z. 8.1874, p. 122. 5 P. Z. S. 1873, p. 641. |