392 Prof. N. S. Maskelyne on New Cornish Minerals [1865. 



common with the lumbricalef, into the extensor aponeurosis, and so to the 

 middle and extreme phalanges. He looks upon this as one characteristic 

 distinction between the hand and foot. In the arrangement which the 

 author believes to be almost general in respect to the insertion of the 

 interossei in the foot, and which supports essentially Mr. Huxley's view, it 

 will be found that the bulk of each tendon is implanted into the base of the 

 first phalanx, blendingwith the lateral ligaments of the metatarso-phalangeal 

 joint, while only a few of the dorsal fibres are sent upwards and forwards, 

 to meet and blend with the slips sent down to the sides of the joint from 

 the extensor aponeurosis. These are not, however, so distinct and powerful 

 as we find them in the hand, and, in their thin and scattered appearance, 

 differ entirely from the insertion of the lumbricales tendons into the more 

 forward part of the same extensor aponeurosis. 



" On New Cornish Minerals of the Brochantite Group." By Professor 

 N. STORY MASKELYNE, M.A., Keeper of the Mineral Department, 

 British Museum. Communicated by A. M. STORY MASKELYNE, 

 M.A. Received February 13, 1865*. 



In March last my attention was drawn to a very small specimen of Killas, 

 with some minute blue crystals on it, associated with a few equally small 

 green crystals. The latter I proceeded to investigate with the goniometer. 

 They proved to have almost identical angles with Atacamite, and, presuming 

 them to be crystals of that mineral, I neglected them in order to measure 

 the angles of the blue crystals. These proved also to belong to the pris- 

 matic system, and evidently were a new mineral. The specimen had come 

 to the Museum from Mr. Tailing, of Lostwithiel, a dealer from whom the 

 National Collection has received a very large proportion of its finest Cornish 

 minerals, and whose attention had been called to this specimen by the 

 novelty of its appearance. Mr. Tailing no sooner was apprised of the in- 

 terest attached to his little fragment of Killas, than he set energetically 

 ' about tracing it to its locality. 



After a short time he succeeded in finding this locality ; and though he 

 has not yet divulged it, he soon forwarded other specimens to me at the 

 British Museum. He has since found fine masses of the minerals, which 

 are described in this memoir, and they are now in the collection under my 

 charge. 



The Killas which usually carries these minerals is of a very friable texture, 

 often occurring as a breccia cemented by the minerals themselves, and at 

 other times coated by them as incrustations. 



Sometimes, however, they are found on it as minute crystals scattered 

 over, and in direct contact with, the rock, or in a succession of layers de- 

 posited on it. In the latter mode of occurrence, the stone, whether Killas 



* Read February 23, 1865: see Abstract, p. 86. 



