Miscellaneous. 357 



Venus magnifica. Ven. testd suhorhiculari, suhcordatd, tumidd 

 aut ventricosd, soUdissimd, valde inmquilaterali ; margines versiis 

 purpurea tinctd, umhones versiis alhidd hrunneo sparsim maculatd ; 

 lincis concentricis , sulcisque radiantibus decussatd ; lineis, antice 

 undosis et paulb elevatis, postic^ obsoletis, medib planulatis et sur- 

 silm spectantihus ; sulcis frequentibus, profundis ; margine ven- 

 trali arcuato, intusque crenato ; dorsali, antice convexo et declivi, 

 postice convexo et vix declivi ; latere postico majore, obtuso ; nati- 

 bus maxime curvatis ; pube, lunuldque prominente cordiformi, 

 livido-purpureis ; ligamento infosso ; superficie internd albidd, im- 

 maculatd; dentibus ut in V. puerperS,. Long. 5* ; lat. 5 poll. 

 Hab. Ticao, on the sands ; Cuming. Mus. Cuming. 

 This sjjlendid 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 costellse. 



ON THE LARTJS 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 

 gpecies are — 



1st. 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^r.9^summer of their attain- 

 ing adult plumage, and others the hood in their first assumption of the black 

 hood. 



