32 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 21, 



5. H. LANCEOLATUS, sp. nov. Fig. 5. 



H. elongatus, postice attenuatus ; aiticulis 12, quorum 10 transversis, penul- 

 timo oblongo, cauda acuta producta. 



This is the smallest of the Lesmahago species. It is elongate, 

 attenuated behind, consisting of twelve body-rings, which are sculp- 

 tured anteriorly, as in the last species, and are all transverse, except 

 the penultimate, which is elongate-oblong. The tail-joint is a gra- 

 dually pointed spine, longer than the preceding joint, and appears to 

 be keeled along the middle. (Its base is less bulbous than it is in 

 our figure.) 



The swimming-feet are narrow, and extend back to the sixth 

 body-joint. 



Locality. — All the above are from the same locality, — Lesmahago 

 in Lanarkshire ; and were discovered in the uppermost Silurian rock 

 by Mr. Slimon*. 



Another species of the genus occurs in the Tilestone of Kington, 

 Herefordshire, and has been for some time known to me. I propose 

 to call it H. Banksii. 



6. H. Banksii, sp. nov. 



H. parvulus, 2-3-uncialis ; capite convexo, parabolico, ad frontem suban- 

 gulato ; oculis gibbis lateralibus, ad medium capitis, prominentibus ; an- 

 nulis trunci valde transversis. 



This small neat species, of which we have many specimens in the 

 Museum of Practical Geology, occurs with Fterygotus and spines 

 both of Crustaceans and of Fish, in the yellow tilestone beds of King- 

 ton, Herefordshire. It is there associated with the Platyschisma 1 

 helicites and lAngula cornea. These are the two species of shells 

 which appear to accompany the fossils of Lanarkshire above de- 

 scribed, — a good argument, therefore, even without other evidence, 

 for regarding those beds as the uppermost portions of the Ludlow 

 rock. 



The head i^\\ inch long, and fully as much broad ; it is semioval, 

 produced and angulated anteriorly, regularly convex, with a thick 

 margin, on which the prominent oval eyes are placed rather more 

 than half-way up the head. They are small in comparison with 

 those of some of the other species. The posterior head-angles are 

 retuse, and the hinder margin is quite plain and even, as in the other 

 species. We do not possess the body, except imperfect portions of 

 the first nine rings ; and these agree in general form with those of 

 the H. lanceolatus. Both have a close scale-like sculpturing on their 

 forward margin, and together with them at Kington occur also tail- 

 spines, scattered in the rock, which may possibly belong to them, 

 and which are narrower than those of the Lanarkshire fossil. As 



* See the preceding paper, by Sir R. I. Murcbison. 



