INSCRIPTIONS OF Till! SPECIES. 187 



completely overlooked by subsequenl writers, but we have little doubt of its identity 

 with Pentatremntites oblonga, (i. B. Sowerby. 



We regard Sowerby's fig. 4 as representing the typical form of .1/. elongatus. Bui 



it is much too rounded and globose in the upper part of the calyx. The enlarged 

 figures of the ambulacra given by Sowerby do not altogether agree with one another. 



In that attached to fig. 1 the exposed lancet-plate is shown, but in the ambulacrum 

 ot' fig. '■) the side plates are represented as meeting in the middle line. This is 

 generally only the ease near the end of the ambulacrum, which is of considerable 

 relative width ; but the lancet-plate is small in proportion, and the side plates resl 

 on a wide hydrospire-plate, which is well shown in PI. XL fig. 15. 



Mesob/as/i/s < longatus is allied to only one species of the same genus, .1/. Sowerbii, but 

 the ambulacra are wider than in that type (PI. VI. fig. 12), whilst the calyx generally 

 presents a more slender outline (PI. VI. fig. 12; PI. VIII. fig. 1); and when other 

 characters of the respective species are examined, the differences appear much more 

 marked. In M. elongatus the base is concave (PI. VIII. fig. 3), in the other species 

 protuberant (PI. VI. figs. 12, 14). M. elongatus, from the length, as compared with 

 the width of the calyx, may be said to represent the position held by Granatocrinus 

 Shumardi, Meek and Worthen l , in the genus Granatocrinus, if, indeed, it be a 

 Granatocrinus and not a Mesoblastus. 



The spiracles in the specimen which we have figured seem to vary considerably in 

 the extent to which they are divided by the deltoid ridge (PL VIII. figs. 2-4). 



Locality and Horizon. Whitewell and Borland District, Lancashire; Settle, York- 

 shire : Carboniferous Limestone. 



Mesoblastus Sowerbii, sp. nov. 



(PI. VI. figs. 12-14 ; PI. VIII. figs. 5, C.) 



Granatocrinus oblongus (pars), E. & C, Ann. & Mag. Nat. Hist. 1882, vol. ix. p. 239. 



Sp. Char. Calyx elongate, angularly barrel-shaped, rather inflated along the ambu- 

 lacra ; summit truncated ; peristome flat, or slightly concave ; base truncated, but 

 centrally protuberant, the protuberance extending below the level of the radial lips ; 

 section pentagonal, with strong projecting angles ; periphery almost equatorial. 

 Basal plates small, forming the central trilobate and protuberant portion of the base. 

 Radial plates very long, more than two thirds the length of the calyx, very much 

 arched, especially in a transverse direction ; bodies small, concave ; limbs very long, 

 with parallel margins, the sides sloping at a high angle, obliquely and sharply 

 truncated above ; sinuses with subparallel sides and slightly thickened edges ; lips 

 small and projecting, but not extending quite as low as the protuberant base; con- 

 cavely-bevelled bands adjoining, and parallel to the edges of the sinuses, are visible 

 on the surface of the plates. Deltoid plates very acutely and unequally rhombic, 



1 Report Gcol. Survey, Illinois. IsCS, vol. iii. t. 18. f. 6 6. 



2b2 



