Professor G. A. J. Cole — On Bclmitrus kiltorkensis, 53 



Baily's discovery* of "a well-marked head (or carapace), to which 

 is attached portions of two of the thoracic segments," Dr. Henry 

 Woodward,- in 1878, accepted this determination, on the basis of 

 sketches furnished to him by Mr. Baily, who had by this time 

 discovered a second, though distorted, specimen. The Kiltorcan 

 Beds, it may be remarked, are of Upper Old Ked Sandstone age, 

 •and are part of the ' Yellow Sandstone Series,' which passes con- 

 formably up into the Lower Carboniferous Shale. They are not, 

 therefore, of such high antiquity as the writer in the Ottaioa 

 Naturalist suggests. 



Fig. 1. — Sketch of the less imperfect specimen of Brlinuriis kiltorhcnsis, Baily, 

 showing the principal features visible with a platyscopic lens. Natural size. 

 The carapace is viewed from the under side. 



Fig. 2. — Sketch of the distorted specimen, viewed from the upper side with the aid 

 of a platyscopic lens. Natural size. The details of the central portion are 

 best seen in this example, though the whole is greatly broadened. 



The question having thus been raised, I obtained the permission 

 of the Director-General of the Geological Survey to examine the 

 specimens preserved in the collections in the Dublin Museum. 

 Mr. Baily's specimens have, at some later time, been relabelled 

 «s ' Limuloides '; but the carapace is certainly not of the hemiaspid 

 type. It presents the continuous unnotched margin shown in 

 ]\Ir. Baily's original drawing. The better specimen is, I feel 

 confident, presented to us from the under side, and shows more 

 detail than has hitherto been attributed to it. The flat border, 

 Imra. wide, is followed by a smoothly curving region, from which 

 the protuberances rise which correspond in part to the glabella in the 

 trilobites. The form of these is best seen from the annexed 

 sketches, which, like Mr. Baily's, have been made from the original 

 specimens. The distorted example is seen both as an external cast 

 and in relief, and the four elevated portions stand out distinctly 

 on it. They seem to have been highest at their margins, a rim 

 thus occurring about a depressed area on each. This feature is also 

 seen in Mr. Griesbach's drawings of the better known species of 

 Helinurus.^ 



The eyes indicated by Baily are based on a thickening that occurs 

 on the edge of the ' glabella,' where it descends to meet the 

 -smoother lateral area. The evidence is slight, but agrees with what 

 ss already known of BeUnurus. 



There are indications of radial ribbings on either side of the 



' "On Fossils obtained at Kiltorkan Quarry, Co. Kilkenny": Report Brit. Assoc, 

 ior 1809, p. 75. 



* " British Fossil Crustacea" (Paheontographical Society), p. 238. 

 ^ *'Brit. Foss. Crust." (I'lil. Soc), pi. .\\.\i. 



