Geological Society, 333 



which most experienced collectors make of stations, dates of capture, 

 ahundance or scarcity, plants t'reciucnted, &c. could be introduced. 

 Such important particulars, if not made use of when the specimens 

 arc described, are only too apt to be lost altogether ; their addition 

 to the text would involve but little more expense, and would cer- 

 tainly increase the sale of the work, which we regret to learn is 

 at present far more limited than its great merit demands. 



We cannot omit, in concluding, to draw especial notice to a most 

 valuable feature of ' Rhopalocera Exotica,' viz. the large space in 

 this volume devoted to the illustrati(ui of African Lycajnidte. The 

 Ethiopian Kegion stands alone in the number of aberrant genera of 

 this family which are peculiar to it ; but it is only quite recently, 

 since the tropical area has been better investigated, that its wealth in 

 species has come to light. As many as eighty-four species, allotted 

 to twelve genera, are figured on the seventeen plates assigned to this 

 family, and, as many of these are small, obscure, and closely-allied 

 forms, it is of signal service to the lepidopterist to have such good 

 figures of them provided. R- T. 



PROCEEDINGS OF LEARNED SOCIETIES. 



GEOLOGICAL SOCIETY. 



June 22nd, 1892.— W. H. Hudleston, Esq., M.A., F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. " Mesosauria from South Africa." By Prof. H. G. Seeley, 

 F.R.S., F.G.S. 



The Author gives an account of specimens of Mesosaurus pleuro- 

 gaster (Seeley) obtained from the shales at the Kimberley diamond- 

 mine. They are of small size, and show generic identity with the 

 Paris type, but indicate an animal with a long tail, with the hind 

 limbs well developed. The centrums of the vertebra are barrel- 

 shaped, contracting to the articular faces, which are conically 

 cupped. The dorsal ribs have the usual subcylindrical character 

 and development ; but the abdominal armour is more like that of a 

 Plesiosaur, only the sternal ribs are thin and flat. The vertebrte 

 appear to give attachment to the dorsal ribs in an unusual way, 

 which suggests the condition in the Thcriodontia, but without 

 distinct tubercles or facets ; so that the slender head of the rib 

 lies in the depression between two centrums. In the early caudal 

 vertebra' the transverse processes are stronger, the neural spines 

 long and compressed, and chevron bones well developed. Details 

 are given of the structure of the tarsus and bind limb. 



A new example of Mesosimrus tenuidens from Albania, preserved 

 in the South African Museum, shows many details of structure 



