ON THE STRUCTURE AND CLASSIFICATION OP THE FOSSIL CRUSTACEA. 45 



has been met with. It will be needful to modify the specific name of Pt. 

 bilobus, as the new form, and ji:>ero mat us ; both have a bilobcd telson likewise. 



If the name is retained, it must be apphed to all three forms thus : — Pt. 

 bilobus, var. inornatus ; Pt. bilobus, xar. crassus* ; Pt. bilobus, \&v. pevornatus. 



In the Quarterly Journal of the Geological Society, vol. xxii. part 1, 

 Februaiy 1867, p. 28, and in the British Association Heport for 1866, 

 p. 180, and Sections, p. 79, I pointed out the affinities of the Limulidie 

 ^\ith the Eurypteridce, and in the first-named paper I recorded all the forms 

 then known which tended to confirm their alliance. 



I have now to notice a new genus from Lesmahagow, Lanarkshire, which 

 offers further evidence in confii'mation of the correctness of the above-men- 

 tioucJ classification. 



It is a small Limuloid formf, the carapace of which measures only 6 Lines 

 in breadth and 2 in length, having 5 thoracic and 3 abdominal segments, all 

 of which appear to be free and distinct. The telson is unfortunately 

 wanting, the specimen being close to the border of the matrix. 



This httle form carries the Limulidce back in time from the Coal-measures 

 to the Uppermost Silurian, a great and important extension. 



I shall take an early opportunity to describe this form in detail, and to 

 work out its relationship to Belinurus on the one hand and Hemiaspis on the 

 other. 



New Lower Lias Crustacean from Barrow-onSoar. 



A new Crustacean, obtained some years since by Sir Philip Egerton, Bart., 

 M.P., from the Lower Lias of Barrow-on-Soar, has since been also found by 

 Mr. Charles Moore, F.G.S., near Bath. It is quite distinct from every other 

 form which I have examined from the Lias or Oohte. Its nearest analogue 

 is the recent Atya scabra of Leach, from South America. The limbs are 

 monodactylous and extremely rugose ; the antenuaj are rigid, and the basal 

 joints thick and spinose, resembling in these points of structure the genus 

 Palinurina. The rostrum is short and curved downwards. The carapace 

 was extremely thin, and less chitinous than in the genera Aer/er and Pcnceus, 

 it is therefore more easily destroyed or distorted. 



I propose to name this new form Prcmtija scabrosa. 



Upper Lias Crustacea from Ilminster. 



Having been favoured with the loan of a large series of specimens for ex- 

 amination from the Upper Lias of Ilminster, collected by Mr. Charles Moore, 

 r.G.S., of Bath, I have been enabled to add a considerable number of genera 

 and species to our list of Liassic Crustacea. 



The two species of Eryon, E. antiquus and E. Moorei, have been already 

 noticed bj- me from this localitv (see Quart. Joui-n. Geol. Soc. vol. xxii. 

 p. 499, pi. 25, fig. 3). 



I have since determined the following genera and species, which will be 

 described at length in a paper by Mr. Charles Moore on the Ikninster Lias, 

 now in preparation J : — 



* This interesting form of bilobus exhibits in one instance well-preserved brancMce, to 

 which attention was called, and drawings of which were shown by Mr. Woodward. 

 They will be figured in the Palwontogi-aphical Society's Monograph on the Mcrosto)iiata. 



t The original specimen was exhibited of this, and also figures and specimens of the 

 other forms from Mr. Slimon's collection, believed to be new. 



I See the Proceedings of the Somersetshire Archteological and Natural-History Eccict 

 vol. xiii. Published November 18G7. Taunton. 



