XLII BULLETIN NO. 23, UNITED STATES NATIONAL MUSEUM. 



giving' tbe major axis the horizoutal line, and be fully appreciated the 

 valne of the ellipses, for, as he observed, "tliese were constants." ('ail- 

 ing on Dr. Carpenter with a letter from Dr. Dunglison, he was told, 

 very kindly, that Dr. Lea required no letter to him. Many branches of 

 natural history were talked over, Foraminiftra, &c. He showed Dr. 

 Lea some fine Orhitellcv, with many varieties which had been described 

 by D'Orbigny and others as distinct species. Of these he had made 

 large drawings, and showed conclusively that the number of species 

 must be greatly diminished. He also showed Dr. Lea his prepared spec- 

 imens, beautifully arranged on glass, with their names written with a 

 diamond point. The structure of the Pinna was finely illustrated by 

 cross and longitudinal sections showing the cells with the basement 

 membrane. The Terchratuhc were particularly beautiful, the foramina 

 being perfectly displayed. In the Unio the structure is very different 

 from tliat of the Pinna, the layers of the latter being imbricate. The 

 epidermal matter, or more properlj- the periosteum, is deposited with- 

 out any structure, while in the Terehratula it is plaiuh' seen to have 

 beautiful openings, which really seem to have opercula. The structure 

 of Ecliinus is very different. Sections of spines of different species 

 differ very much. The cross-section has somewhat tbe appearance of 

 the cross-section of a tree, but the tubular form differs, so that in the 

 Echinus it looks like lace- work. Afterwards they went over the Vniones 

 which Dr. Lea had taken him, noticing more particularly the undula- 

 tions of the beaks and the different ages. He was much interested in 

 these differences, which he had never before observed. He invited Dr. 

 Lea to dine with the Philosophical Club, composed of forty-seven work- 

 ing members of the Eoyal Society, the number of members being 

 restricted. But Dr. Lea, having been previously invited to the dinner 

 l)y Professor Forbes, said he would meet him there. 



Dr. Lea returned a visit from William J. Hamilton, secretarj^ of the 

 Geological Society, whom he had met at the congress of German scien- 

 tists at Wiesbaden the previous year. He found him engaged in exam- 

 ining a collection of mollusca and fossils sent by the well-known Rajah 

 Brookes from Borneo, which were particularly interesting. He gave 

 to Dr. Lea a Unio, a Cyrena, and a curious Cyclostoma which had spines. 

 A few days afterward he dined with the Philosoj^hical Club, where 

 Sir Roderick Murchison presided. He requested Dr. Lea to take 

 the seat on his right. The distinguished members present were 

 Lyell, Carpenter, Forbes, Graham, Wheatstone, Sharpey, Sabine, Hoff- 

 man, Miller, Crosse, Hooker, Hopkins, &g. The president asked the 

 secretary if he had anything to bring before the club. On rising the 

 secretary said, " There is a gentleman present who, though a foreigner, 

 can hardly be considered a stranger," aiul he hoped that Dr. Lea had 

 something new which he could communicate to them. Dr. Lea then made 

 some remarks on the two Saurians, descriptions of which he had pub- * 

 lished, relating to their position in the strata, one in the New Red Sand- 



