46 CARBONIFEROUS ENTOMOSTRACA. 



Carboniferous rocks by the description and illustration of twenty- two forms (including 

 Entomoconchus Scouleri) from the Lower Carboniferous strata of Ireland, in his ' Synopsis 

 of the Characters of the Carboniferous Fossils of Ireland' (4to, Dublin, 1844). Having 

 been enabled, through the courtesy of Sir Richard Griffith, Bart., to examine the 

 original specimens, we communicated to the ' Annals Nat. Hist.' for July, 1866, a critical 

 notice of the whole, and arrived at the following conclusions as to the specimens of 

 E. Scouleri?- 



" 1. Entomoconchus Scouleri. Lower Carboniferous Limestone ; Little Island, Cork. 

 ' Synops. Carb, Foss. Ireland,' p. 164. Griffith, " List of Localities " (' Journ. Geol. Soc. 

 Dublin,' vol. ix), p. 68. A weathered shell [not " cast "] in grey crystalline fossiliferous 

 limestone. 



" 1*. Another shell, in similar limestone; Millicent, Clane, Co. Kildare. 



"1**. Another specimen (labelled ^ E. Scouleri, Upper Carboniferous Limestone; 

 Black Lion, Enniskillen, Co. Leitrim,' ' Localities,' p. 80) is a dark-coloured crystalline 

 shelly limestone with a Cyclus!'"' 



In Prof. M'Coy's figures and descriptions of E. Scouleri the hinge-line is by mistake 

 referred to the anterior extremity, and the relations of the other margins are consequently 

 misconstrued. His figures pubUshed in 1839 are large and carefully drawn, but those 

 of 1844, also those by Phillips and De Koninck, are not of sufficient size, nor exact 

 enough, to serve the purposes of the naturalist. 



The characteristic feature in Entomoconchus, namely, the anterior peak, with a fissure 

 beneath, formed by a sudden, though slight, inward curve of the edge of each valve, just 

 below the antero-dorsal region, and analogous to the Cypridinal beak and notch, was not 

 noticed until 1863, when we pointed out that Entomoconchus is one of the CypridinacUe 

 in a provisional notice of the Entomostraca of the Carboniferous Period read before the 

 British Association.^ 



Generic Description. — The carapace of Entomoconchus is bivalved and subglobose ; 

 valves subequal, smooth, thick (^th inch and more). In some instances, where large 

 individuals are crowded together (Kildare and Bolland), the middle portions of some 

 valves appear to be -j^th inch thick, but this may possibly be due to the close approxima- 

 tion of valve within valve. Sometimes a very faint reticulate structure is recognisable in 

 well-preserved shells. The left valve strongly overlaps the right valve in the antero-dorsal 

 region, less so posteally, and slightly at the ventral border. This kind of overlap exists in 

 two of Dr. Baird's Cypridina, C. Zelandica and C. alhomaculata (' Proc. Zool. Soc.,' 



^ See 'Annals Nat. Hist.,' ser. 3, vol. xviii, p. 41, 



2 For a full account of all that is known of this curious little fossil Crustacean and its allies see Mr_ 

 Henry Woodward's exhaustive memoir in the ' Geol. Mag.,' 1870, vol. vii, pp. 554 — 560, pi. 23. 



3 See 'Report Brit. Assoc.,' Newcastle-on-Tyne, for 1863, Trans. Sect., p. 80; also 'Canadian 

 Naturalist and Geologist,' new ser., vol. i, 1864, p. 236; ' Neues Jahrbuch fur Min. Geol.,' &c., 

 1864, p. 54 ; and ' Geologist,' vol. vi, p. 460, 1863. 



