52 MR. W. H. PEASE ON SISTRUM CANCELLATUM. [Jan. 10, 
taken from under a stone. Mr. Gould thinks that, by destroying 
insects and their larvee that may attack the ova and fry of fishes, 
these birds may do great service. 
Mr. Macgillivray found beetles and water shells (Zymnea and Ancy- 
Ius) and the larvee of Ephemera, Phryganea, and other aquatic insects. 
Sir W. Jardine, in his ‘ Birds of Great Britain,’ says, “‘ In one part 
of Scotland, sixpence per head is given for these birds. In another 
district, 548 were killed in three years.’ He adds, ‘‘ The ova of any 
kind of fish we have never detected in the stomach or intestines ; nor 
do we think that they habitually frequent the places where the 
spawn would be deposited ; and if they did, we would deem it almost 
impossible that they could reach it after it was covered in the 
spawning-bed,” &e. 
So that I hope we may fairly acquit this interesting little bird of 
the depredations of which it has so often been accused ; but I hope 
that we shall ere long see the Water-Ousel, with the Little Grebe 
(Podiceps minor), in the Society’s fish-house, where a better oppor- 
tunity will be afforded of learning its habits. 
As is well known, this bird has been variously classed by different 
writers. Mr. Gould, in the work before quoted, says he regards 
Cinclus as one of the isolated forms of ornithology, and that it has 
some remote alliance with the genera Troglodytes and Scytalopus 
and their allies. In my next communication I hope, by a careful 
comparison of the skeleton of this bird with those of the other 
Merulide, to come to a more definite conclusion on this subject. 
7. On THE SYNONYMY OF SISTRUM CANCELLATUM. 
By W. Harper Prasz, Corr. Mem. 
We find a great discrepancy, as to the name of this species, among 
the several authors who have noticed it. It was originally described 
by Quoy and Gaimard (Voyage de |’Astrolabe, vol. i1. p. 563, pl. 37. 
figs. 15, 16) as Purpura cancellata. 
The next author who noticed it was De Blainville in his Monograph 
of Purpura, Nouv. Ann.du Mus., 1832, p.221. He refers correctly to 
the ‘Voyage de I’ Astrolabe,’ but names it “P. fenestrata,” possibly by 
mistake in copying. His name is consequently a synonym of P. can- 
cellata. Deshayes, in his edition of Lamarck, gives the description as 
P. fenestrata, Blainv., referring correctly to the figure and description 
by Quoy and Gaimard, as well as to that of De Blainville. Kiener, 
most surprisingly, does not notice it. Reeve discards both the names 
of Blainville and Quoy & Gaim., but describes and figures it more 
correctly than had been done previously, under the name P. elongata, 
Blainv. We can find no description of such a species by De Blainville. 
In his Monograph, however, on pl. 10, fig. 9, a shell is figured to 
which he attaches the name P. elongata; but no corresponding de- 
scription appears in the text. Dr. Gould, in his ‘ Mollusca of the 
U. S. Exploring Expedition,’ figures and describes the animal, 
following Reeve in naming it P. elongata, Blainv.; but he refers to 
