Miscellaneous. 357 
Venus macnirica. Ven. testd suborbiculari, subcordatd, tumidd 
aut ventricosd, solidissimd, valde inequilaterali ; margines versis 
purpurco tinctd, umbones versis albidd brunneo sparsim maculaté ; 
lineis concentricis, sulcisque radiantibus decussatd ; lineis, antic 
undosis et pauld elevatis, postice obsoletis, medio planulatis et sur- 
sim spectantibus ; sulcis frequentibus, profundis ; margine vea- 
trali arcuato, intusque crenato; dorsali, antice convezo et declivi, 
postice convezo et vix declivi ; latere postico majore, obtuso ; nati- 
bus maxime curvatis; pube, lunuldque prominente cordiform?, 
livido-purpureis ; ligamento infosso ; superficie internd albidd, im- 
maculatd ; dentibus ut in VY. puerpera. Long. 5°; lat. 5 poll. 
Hab. Ticao, on the sands; Cuming. Mus. Cuming. 
This splendid shell is most closely allied to puerpera, but the ces- 
sation of the concentric ridges on the posterior side, the tinge of 
purple which environs the whole margin, and the absence of any 
coloured rays, enable us at once to separate them. The concentric 
lines gradually become less elevated and more distant towards the 
lower margin, and finally (in the adult) entirely disappear. The ra- 
diating sulci in aged specimens are so broad at their extremity as to 
give the interstitial spaces the appearance of costelle. 
ON THE LARUS CAPISTRATUS, TEMM. 
At the meeting of the Zoological Society, May 27, Mr. W. Thomp- 
son read a paper to prove that the Larus capistratus, 'Temm., is not 
a distinct species from L. ridibundus, and exhibited a series of speci- 
mens of both forms in different states of plumage obtained in the 
neighbourhood of Belfast. ‘The differences between these supposed 
species are— 
Ist. In size; but a female specimen of L. ridibundus, with black 
hood, bill and legs arterial blood-red, was exhibited, agreeing in the 
size of body, tarsi, &c. with L. capistratus. 
2nd. The colour of the tarsi and toes attributed to L. capistratus, 
and as distinguishing it from L. ridibundus, is a mere transition shade, 
through which all individuals of the latter pass before the arterial 
blood-red hue is attained. 
3rd. The disposition of black or brown on the head, its taking the 
form of a mask, as in L. capistratus, or as a hood, as in L. ridibundus, 
is either transitional or accidental*, and the shade of colour com- 
monly varies from the “‘ broccoli-brown”’ of the former to the deeper 
tint of the ordinary L. ridibundus. 
A specimen of the L. capistratus, purchased at the sale of Bullock’s 
collection by Dr. Leach, and believed to have been one of the first 
birds seen by Temminck, to which he gave this name, is now in the 
British Museum. By the kindness of Mr. George R. Gray, the au- 
thor was enabled to make a critical comparison of this bird with the 
specimens exhibited, and, excepting in the smaller size of the toes and 
webs of feet, there was no difference between it and some of them ; 
* Mr. Thompson stated that he had known it to be both transitional and 
accidental, i.e. for birds to exhibit the mask the first summer of their attain- 
ing adult plumage, and others the hed in their first assumpticn of the black 
hood. 
