42 S PEOCELLAEIID^. 



HALOCYPTEXA. 



Halocyptena, Coues, Proc. Acad. Philad. 1864, p. 78 ; Salvin, Cat. Birds Brit. Mas. xxv. p. 346 

 (1896). 



The single member of this genus is a small brown bird, very similar to the Storm- 

 Petrels in appearance, but differing in form. It may at once be distinguished by its 

 cuneate or wedge-shaped taU. Like Procellaria, the present genus has the tarsus 

 longer than the middle toe and claw, but it has also a very small bUl, with prominent 

 nasals which give the culmen a humped appearaiice. 



Only one species is known, which inhabits the seas and islands on the west coast 

 of America from the Gulf of California to the Bay of Panama, 



1. Halocyptena microsoma. 



Halocyptena microsoma, Coues, Proc. Acad. Philad. 1864, pp. 79 ', 90 ^ ; Baird, Brewer, & Ridgway, 

 Water-Birds N. Amer. ii. p. 402' ; Towns. Proc. U. S. Nat. Mus. xiii. p. 141 * ; Salv. Cat. 

 Birds Brit. Mus. xxv. p. 346'; Oates, Cat. Eggs Brit. Mus. i. p. 147, t. 11. fig. 1'. 



Fuliginoso-nigra, vix schistaceo adambrata ; tectricibus primariomm, ala spuria, remigibas et rectricibus 

 nigerrimis ; tectricibus majoribus pallidioribns, bromiescentioribus, vix conspicois ; corpore toto sabtus 

 magis chocolatino-bruimeo ; subalaribus pectore concoloribus, vix bnmnescentioribus; tectricibnB margina- 

 libus nigris : rosfcro et pedibns nigris. Long, tota circa 5'5, alae 4-75, caudse 2-0, cnlm. 0*4, tarsi 0-9, 

 dig. med. cum ungue 07. (Descr. feminae adultae ex Mazatlan. Mus. nostr.) 



Hob. San Benito Is. {Anthony^); Lowee California, San Jose del Cabo {Xantus ^ ^ ^). 

 — Mexico, Mazatlan (Forrer ^) ; Bat of Panajia {Townsend *). 



In general appearance this species resembles Procellaria tethys, but is disting^uished 

 by its wedge-shaped tail. It would appear to vary somewhat in size, as the female 

 from Mazatlan has the wing only 4'75 inches in length (Salvin makes it but 4-65). 

 A male from San Benito Island has the wing 4"85 inches, and a female from the same 

 place 5 'OS. The Mazatlan bird is iu somewhat worn condition, and does not show the 

 browner greater upper and lower wing-coverts, as do the fresher plumaged birds from 

 San Benito. 



H. microsoma was first discovered by the late John Xantus at San Jose del Cabo, in 

 Lower California, and it has since been met with on some of the adjacent islands 

 off the western coast. Mr. Forrer procured a single specimen near Mazatlan 5, 

 and in March 1888 a bird of this species flew on board the ' Albatros ' in the Bay 

 of Panama. 



Eggs collected by Mr. A. AV. Anthony on the San Benito Islands are in our own 

 collection and in that of the British Museum. They are of an elliptical or broad-oval 

 shape, white, with a very few minute rufous dots — so small that they might easily 

 escape notice — scattered all over the shell. 



