238 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 9, 



the lower lateral lobes ; it is placed very forward, and quite apart from 

 the glabella. Large and small tubercles cover the whole surface, 

 some of the former appearing almost spinous. The larger tubercles 

 are symmetrically disposed, about four pairs being placed at regular 

 intervals along the forehead lobe. 



This new species is named after my friend J. W. Salter, Esq., of 

 the Geological Survey of Great Britain, in acknowledgement of his 

 kind assistance in determining the species, and of much valuable in- 

 formation received from him. 



5. L. Barrandii, n. sp. Pl. XXVII. fig. 10 ; and Pl. XXVII. bis, 

 fig. 5. 



Strong tubercles of unequal size cover the whole surface of the tail, 

 which is almost semicircular, its length being only two-thirds of its 

 breadth ; the axis is wider than either of the side lobes, — it is sub- 

 conical, and moderately convex in its upper part for rather more than 

 half the length of the tail, then contracted suddenly to less than half 

 its former width, but does not taper to a point ; it is depressed in its 

 lower portion, so as to subside into the general surface of the tail 

 considerably in advance of the bifurcate apex. The upper part of 

 the axis is divided into three distinct rings, followed by a broad cen- 

 tral tubercle. Each of the flattened sides of the tail consists of three 

 foliaceous pleurae or lobes terminating in broad projecting teeth, and 

 separated from each other by narrow sharp furrows ; each lobe is 

 marked obliquely along its middle by a groove ; the two upper lobes 

 are directed outwards, their tips, projecting and acute, are recurved ; 

 the third or posterior lobe is directed entirely backwards, and even 

 inwards, to meet the corresponding lobe of the opposite side, from 

 which it is separated by the broad terminal notch. The pleural 

 grooves of the two upper lobes extend nearly to the tips, but run only 

 a short distance in the posterior lobes. The incurved under portion 

 is concentrically striated. 



This remarkable species has been named after my friend and 

 correspondent M. Barrande, of Prague, whose forthcoming work on 

 the * Systeme Silurien du centre de la Boheme' vvdll doubtlessly en- 

 hance a reputation already well established. 



L. Bucklandi is of more frequent occurrence than the other spe- 

 cies, which are rare. 



EXPLANATION OF PLATE XXVIL 



Fig. 1 . Lichas Bucklandi ; a small specimen differing slightly from the usual form. 



Fig. 1 a. Ditto, upper side, magnified. 



Fig. 1 b. Ditto, lower side, magnified. 



Fig. 2. The same species, of the ordinary form. 



Fig. 3. Lower side of a young specimen, with the front of the head very angular. 



Fig. 3 a. Ditto, magnified. 



Fig. 4. Lower side of a full-grown specimen. 



Fig. 5. Tail of a young indi^4dual. 



Fig. 5 a. Ditto, magnified. 



