210 Transactions. —Zoology. 
Hutton (“ Cat. Birds N.Z.,” p. 41); and Z. bulleri, Potts (Ibis, 1872, p. 38) ; 
as I can state positively, having type specimens of all these so-called species, 
and besides the types of Bruch from the Museum at Mayence. . 
The colouration of the bill varies (after season and age) from black to 
reddish-yellow with black tip (this latter form represents Z. bulleri, Potts), 
that of the feet from black to reddish. I have seen intermediate specimens. 
This species is characterized by its slender bill, and chiefly by the white on the 
inner web of the four first remiges, which are white shafted. The extent of 
this white on the remiges varies after age, as is also the case in our 
L. ridibundus and L. lambruschius, which show also a similar variation in 
respect to the colouration of bill and legs. 
I shall treat this species also in extenso, and make it thoroughly known. 
Sterna—(!) n. sp. Potts, Trans. N.Z. Inst., IL, p. 77. 
This is certainly St. nereis, Gould. 
Hydrochelidon leucoptera, Hutton, (Cat. Birds N.Z.,” p. 43.) 
I suggest that this species has been confounded with H. hybrida, Pall. 
(fluviatilis), at least I come to this conclusion in comparing the measurements 
given by Capt. Hutton. 
PROCELLARIDA. 
The species of this family are, with certain exceptions, far from being well 
known. I should like to examine specimens of this group, having seen from 
New Zealand only a single specimen of Prion ariel. 
Puffinus gavius, Forster. 
I think Capt. Hutton is quite right to refer his P. assimilis and 
opisthomelas to this since Forster almost unknown species. 
P. opisthomelas, Coues, is, according to my views, not so positively to be 
united with gavia as Capt. Hutton thinks ; at least a comparison with the 
types would be the only way to settle the question. 
Puffinus tristis, Forst. 
Layard’s “ Mutton Bird” from New Zealand, named by him P. brevicau- 
datus (Ibis, 1863, p. 245), belongs apparently to this species. 
I am not as sure as Capt. Hutton whether P. (Nectris) amaurosoma, Coues, 
is indeed identical, and I should hesitate to declare this with certainty until 
I had compared specimens, 
Prion ariel, Gould. 
The differences between this species and Pr. turtur are indeed very minute, 
and the identity of both seems very possible to me. T should like to see 
series of these allied species in order to be clear about their specific value. 
