412 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 14, 



sinus or place of the notch, and without any dorsal furrow. Such 

 carapaces are not rare in some Lower Carboniferous strata. 1. 

 Polycope Burrovii is subglobular, from Settle. 2. P. simplex, oval, 

 obliquely truncated at the antero-ventral edge, is common at Cork 

 and Duleek, Ireland ; and Dr. Rankin found seventeen in one iron- 

 stone nodule from Braidwood, near Carluke. It is somewhat like 

 Cypridina primceva ; but the want of the notch and beak is its cha- 

 racteristic difference. 3. P. Youngiana, from the Lower Lime- 

 stone of Campsie, near Glasgow, is oval and slightly pinched-in or 

 indented on the antero-ventral quarter, and has a striolate ornament. 

 This genus is the last described in tbat portion of the Monograph 

 which is now completed. Cytherella, belonging to an alhed group, 

 is known to occur in the Mountain Limestone ; and Leperditia, 

 Beyrichia, KirJcbya, Moorea, and Entomis, all palaeozoic genera, 

 abound ; forms referable probably to Cythere, Cypris, Candona, &c. 

 are also known in the Carboniferous formations. 



Discussion. 



Mr. Gwtn Jeffreys inquired as to the greatest depth at which 

 recent marine Entomostraca had occurred. So far as he knew, they 

 were abundant in the Littoral and Laminarian zones, and very scarce 

 in the Coralline. He was not aware of their occurrence at a great 

 depth. 



Prof. T. Rupert Jones stated that in the Carboniferous limestone 

 the Cypridinidse frequently occur in layers, but he thought these 

 were deposited at no great depth, probably not more than 100 

 fathoms. The greatest depth from which he had seen Entomos- 

 traca from the Atlantic was upwards of 1000 fathoms. These, 

 however, belonged to different genera from those which he had 

 been describing. Their modern congeners, though mounting to the 

 surface in the evening, no doubt descended to considerable depths 

 during the day. 



Max 14, 1873. 



The following communications were read : — 



1. On the genus Pal^ocoryne, Duncan & Jenkins, and its Affi- 

 nities. By P. Martin Duncan, M.B.Lond., F.R.S., Y.P.G.S., 

 Professor of Geology in King's College, London. 



[Plate XIV.] 



Five years have elapsed since I completed the description of a very 

 interesting fossil from the lower Carboniferous shales of Ayrshire 

 and Lanarkshire, with the assistance of Mr. H. M. Jenkins, F.G.S. 



The results of our labours were read before the Royal Society on 

 June 17, 1869, and were subsequently published in the Philosophical 

 Transactions, vol. clix. p. 693 (1869), under the title of " On Palceo- 



