On new MoUuscafrom South Africa. 163 



Professor Marah fii^urcs the base of the skull of [Theco- 

 dontosaurus] platyodon^ of which no example is known in this 

 country in any niust'uni. 



Figures are also giveii of the bones of the left fore lejij of 

 the same species, in which are shown the scapula and'cora- 

 coid, the humerus, radius, ulna, two carpal bones, and five 

 metacarpals. There are three digits bearing claws with two, 

 three, and four j)halanges ; the fourth digit has three minute 

 phalanges, and in the fifth a hypothetical phalange is indi- 

 cated. The claws decrease in size from the tirst to the third. 

 No such specimen exists in this country. The forms of the 

 bones are similar to those which 1 have attributed to Palceo- 

 saurus platyodon, with which they correspond in proportion, 

 though, as the figure is one-fourth natural size, the animal 

 appears to be slightly smaller tlian that of which I have given 

 particulars. It is unexpected to find so Crocodilian a type of 

 limb witii the metatarsals extended as though they were 

 carried vertically. 



As the Bristol Museum specimens all came from a working 

 long since closed, it would be interesting to learn the source 

 from which these important new materials have been obtained. 



XVII I. — Descriptions of Four new Species of Terrestrial 

 MoUuscafrom South Africa. By JaMFLS CosMO Melvill, 



M.A., F.L.S., and John IIkn-ry Ponsonby', F.Z.S. 



[Plate XII.] 



Ziiigis delicata, S[). n. (PI. XII. figs. 1, 1 a.) 



Z. ter^ta iinperforata, depresso-orbiculari, tenui, nitida, corneo- 

 suceineata ; aufractihus sex, apud sutiiras impressis, fere la;vibus, 

 sub lente infra suturas et circa regionem umbilicarem transversim 

 teuuissimo striatis, striis mox evauidis, loiigitudinaliter irregu- 

 lariter oblique liratis, ultimo anfractu apud medium Ucvissimo; 

 apertura ovata ; peristomate tcuui, axi coluraellari albescente, 

 l)aulhim incra.ssato. 



Long. 0, lat. Kj mill. 



Hah. Knysna {Cox). 



An extremely beautiful, imperforate, transparent species, of 

 a dark brown warm amber colour ; thin, fragile, depressed 

 orbicular in form, six-whorled, with much flattened spire and 

 apex; apparently quite smooth and shining, but with the aid 

 of a lens the. -surface below the suture is seen to be very finely 



