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uncia) presented bj^ Capt. H. I. Nicholl, 1st Bedfordshire Regiment, on 

 February 18th, and to a pair of Prjevalsky's Horses [Equus Prjevalshii) 

 received on deposit on February 28th. — Mr. E. N. Buxton gave an 

 account, illustrated by lantern-slides, of his recent sporting-expedition to the 

 Egyptian Soudan, in the course of which he traversed the route along the 

 White Nile between Khartoum and Fashoda. Mr. Buxton exhibited a 

 series of photographs of Mammals and Birds taken from living specimens. 

 Among these were views of the White-eared Kob [Cobus leucotis) and the 

 Tiang [Damaliscus tiang). — Dr. H. Lyster Jameson, M.A., read a paper 

 "On the Origin of Pearls." The author's observations referred especially to 

 Mytilus edulis^ the Common Mussel. The pearls were found to be due to the 

 presence of parasitic Distomid larvae, which entered the subcutaneous tissues 

 of the Mussel and became surrounded with an epidermal sack similar in its 

 characters to the outer shell-secreting epithelium of the mantle. If the 

 Distoma died in the sack it became calcified, and formed the nucleus of a 

 pearl; the pearl arising, like the shell itself, from the calcification of the 

 cuticle of the epithelial cells. The parasite sometimes migrated out of the 

 sack, in which case the nucleus of the pearl was inconspicuous. Dr. Jame- 

 son had investigated the life-history of this parasite, and found that it arose 

 as a tail-less Cercarian larva, in sporocysts, in Tapes decussatus and Cardium 

 edule. He had succeeded in infecting Mussels from Topes in an aquarium. 

 The adult stage of this parasite was apparently Distoma somateriae Levinson, 

 which occurs in the intestine of the Eider Duck, and wich the author had 

 found in the Scoter or Black Duck [Oedemia nigra). The complicated life- 

 history of the parasite, and the absence of organs of locomotion in the 

 Cercana-stage, sufficed to account for the anomalous and hitherto inexpli- 

 cable distribution of pearlbearing Mussels. Dr. Jameson had found that 

 pearls were caused by similar parasites in several other species of Mollusca, 

 including some of the Pearl-Oysters ; and he believed that the artificial in- 

 fection of the Pearl-Oysters could be effected in a similar manner to that 

 which he had found successfull in the case of the Common Mussel. When 

 this was achieved the problem of artificially producing pearls would be solved. 

 — Dr. P. L. S dater enumeratad the species of Parrots of which specimens 

 were contained at the present time in the Society's collection — 109 in all, 

 — and made remarks on some of the rarer species. — Mr. G. T. Bethune- 

 Baker, F.Z.S., read a paper entitled "A Revision of the Amblypodian 

 Group of Butterflies of the Family Lyeaenidae}'' The author was of opinion 

 that the whole of the species of this group could be conveniently relegated 

 to six genera — viz. : Amhly podia ^ Iraota^ Surendra^ Thaduka^ Mahathala^ and 

 Arhopala^ — and that it was useless to split up the genera further, as had 

 been attempted by some Entomologists. — A communication from Mr. 

 Martin Jacoby, F.E.S., contained the descriptions of sixty-three new 

 species of Coleoptera of the family Halticidae from Central and South Ame- 

 rican. — P. L. Sclater, Secretary. 



Dmck von Breitkopf & Härtel in Leipzig. 



