Contributions to Fossil Crustacea. 389 



east of Colnary Eiver (30, vi, 1897)," and shows a nearly entire 

 head-shield and a portion of five thoracic segments of a small Limu- 

 loid Crustacean, probably near to Bellinurus regines, Baily, from the 

 Irish Coal-measures, and measuring in its present imperfect state 

 5 mm. in breadth and 4 mm. in length. The cephalic buckler is 

 twice as broad as it is long ; the angles of the shield are moderately 

 produced, and the ocular and median ridges of the shield are very 

 distinctly marked, and also the position of the compound eyes ; the 

 thoracic segments are distinct, and sharply pointed at their free 

 extremities. The margin of the head-shield is slightly thickened 

 and raised, and the front margin somewhat depressed. The telson 

 or tail-spine is not preserved. Each specimen is intaglio. 



2. The second specimen obtained (" 6, vii, 1897 ") is labelled from 

 the " Aster oplnjllites or 6th cutting east of Eiversdale, Colchester Co., 

 Nova Scotia." Although only one side of the specimen and the telson 

 are preserved, it happens to take in rather more than one-half, so that 

 by tracing and reversing the outline one obtains a very correct idea 

 of the form of the entire animal (PL XV, Fig. 2). The specimen is 

 larger than No. 1, measuring 9 mm. in length and 7 mm. in greatest 

 breadth when restored. The artist did not detect the ocular line in 

 this specimen, but it is really present as a minute depressed line 

 outside the glabella, having a deeper spot where the compound eye 

 was situated. Three radiating lines seen on the right side of the 

 head-shield are probably traces indicating the presence of some of 

 the six pairs of maxillipeds or jaw-feet seen in the modern King- 

 crab {Limulus). The cheek - spines of the head - shield are well 

 developed, and extend backwards to the 4th thoracic segment. Five 

 well-defined thoracic segments can be distinctly observed, and two 

 (or three ?) shorter abdominal ones in front of the telson. The 

 lateral margins or pleura of these thoracico-abdominal segments 

 appear to be distinctly truncated, unless, as is just possible, their 

 pointed extremities may have been detached and have adhered to the 

 counterpart impression of the specimen which has not been preserved. 

 The median axis of these segments rapidly diminishes in breadth 

 from the head towards the telson, as is seen to be the case in 

 Bellinurus reginm. The telson or tail-spine is robust, and rather 

 more than one-third of the entire length of the animal. 



As stated elsewhere — see Pal. Soc. Mon., " Brit. Foss. Crustacea : 

 The Merostomata," Part V (Xiphosura), 1878, p. 236— we believe that 

 the five segments composing the thorax in Bellinurus were free and 

 moveable, as in the larval stages of the young of the living Limulus 

 polyphemus and L. Moluccanus, and that such was also the case 

 in Neolimulus falcatus, H, Woodw., from the Upper Silurian, 

 Lesmahagow, Lanarkshire, the earliest Limuloid Crustacean that 

 we know. 



Although Bellinurus is a very ancient type of Limulus, it has not 

 at present been found in rocks of earlier age than the Coal-measures, 

 nor can we assert that the black, grey, and glossy shales of 

 Eiversdale, Colchester Co., Nova Scotia, in which these specimens 

 occur, are older than Carboniferous. 



