358 Annals of the Caknegie Museum. 



size, with the cranium of Audubon's Shearwater (PI. XVI, fig. 6; 

 PI. XVIIII, fig. i6).'-' It has the same well-marked median furrow 

 on the superior aspect between the frontals posteriorly, and the same, 

 very narrow though rather deep, supraorbital glandular depressions — 

 which are only separated from each other by 2.5 mm. — in the frontal 

 region between the orbits on the top of the cranium. 



The superior mandible is slender and the external narial apertures 

 elongate and narrow. Distally, it is decurved, especially enlarged, 

 and ends with an acute, sharp-pointed apex. The interorbital septum 

 presents unusually large vacuities, and the pars planar are very small, 

 projecting outwards in each case as an independent process. With 

 but slight departures, the characters seen in the osseous structures of 

 the basis cranii are the same as we find them to be in all Shearwaters, 

 and more or less like the corresponding ones in a Petrel of the genus 

 ^strclata. Longitudinally, from the most posterior point in the 

 median line of the supraoccipital prominence to the distal apex of the 

 premaxillary, this cranium measures 6.4 cms., and the transverse 

 diameter, between the tips of the postfrontal processes, equals in 

 width 2.35 cms. In short, this cranium belonged to a small species 

 of a typical Pttffinus. 



Coues gives the length of the tarsus, in the case of Pnffinns andu- 

 boiii, as 1.60 (or an inch and six-tenths) (Key, 5th Ed., p. 1036), 

 while the tarsus in the species here being described has a length of 

 but 1.50, or even less in the case of a specimen of that bone found in 

 the McGall collection. It was a much smaller species than the one 

 which furnished the skeleton marked "Pnffinns ohsciirus" in the col- 

 lection of the U. S. National Museum (No. 17724), and Audubon's 

 Shearwater was possibly the Pnffinns ohscnrns of Gmelin. certainly 

 so of Coues and other ornithologists of a few years ago. It then 

 became P. audnboni of Finsch (P. Z. S., 1872, p. 11 1). So, the 

 skeleton just referred to (No. 17724) being that of a very small 

 Shearwater, it brings the matter to a point where Mr. Maynard would 

 have to show that the sternum and shoulder-girdle he sent me be- 

 longed to a specimen of Audubon's Shearwater, now called Pnffinns 

 Ihcriuinicri in the last A. O. U. Check-List. It is a very different 

 sternum from the one belonging to the aforesaid museum (No. 

 17724), and a much larger bone — too large, it strikes me, for the 

 sternum of Audubon's Shearwater (Pnffinns IJicnninieri). If the 



