OF THE GALAPAGOS ARCHIPELAGO. 507 
be attributed to age, or perhaps to the not too accurate colouring of the plate. There 
is shown too, in the latter, a white spot near the eye, which I have not been able to 
trace in the Museum example. 
Genus PROCELLARIA. 
An oceanic genus of nearly universal range. 
PROCELLARIA TETHYS. (Plate LX XXVIII. fig. 2. 
Procellaria tethys, Bp. Notes Orn. p. 92, et Consp. ii. p. 197. 
Fuliginoso-nigra: tectricibus alarum mediis et corpore subtus brunnescentioribus: 
tectricibus subalaribus fuliginoso-brunneis, tectricibus caude superioribus elongatis, 
omnino albis; uropygio dorso concolori; rostro et pedibus nigerrimis: long. tota 6-0, ale 
52, caude rectr. ext. 2-4, rectr. med. 2:2, tarsi 0°85, dig. med. ‘70, rostri a rictu ‘65. 
Obs. P. pelagice affinis, sed tectricibus caude magis elongatis et apicibus omnino 
albis, alarum tectricibus mediis brunnescentioribus, cauda sensim furcata, tectricibus 
subalaribus et axillaribus omnino fuliginosis distinguenda. 
There is a specimen of this species in the British Museum, marked in Bonaparte’s 
handwriting “ P. tethys, Bon.”, and referred to by him in the ‘Conspectus.’ It bears 
the mark 193; but no record of its origin or locality is extant. 
As it answers to Bonaparte’s description, and agrees with the type in the Paris 
Museum (which I have lately examined), I have no doubt it belongs to the species 
obtained by Néboux in the Galapagos Islands. The species seems to be little known, 
no specimen having come under Dr. Coues’s observation when engaged in compiling his 
monograph of this family. 
Mr. Gray refers this species to P. pelagica in his ‘ Hand-list’ (iii. p. 103), having 
apparently overlooked the differences which distinguish it. The plate taken from the 
British-Museum specimen, will, I trust, tend to establish Procellaria tethys in its rightful 
position. 
Genus CESTRELATA. 
This genus of Procellariide has a wide range in both the Atlantic and Pacific Oceans, 
the species being most numerous in the southern temperate zone. In the Atlantic a 
single species ranges as far north as the Canaries, where @. mollis is found. In the 
Pacific the Galapagos Islands appear to be the limit of the northern range. The species 
there found, which I describe below, has its nearest ally in a West-Indian Petrel which 
has strayed to the coasts of Europe. 
CESTRELATA PHAOPYGIA, sp.n. (Plate LXXXVIII. fig. 1.) 
Supra brunnescenti-nigra fere unicolor, dorsi plumis cinereo stricte marginatis ; fronte, 
loris, corpore subtus, pagina alarum inferiore (nisi in margine), et crisso albis: remige 
primo omnino nigro, remigibus reliquis in dimidio basali pogonii interni albis: rectri- 
cibus dorso concoloribus, in pogonio interno basin versus albis; tarsis et pedum dimidio 
