DESCRIPTIONS OF Till- SPECIES. 201 



sides, liasal [dates robust, gently convex, forming a strong obtuselj conical cup; 

 interbasal sutures not in concavities. Radial plates long and narrow, parallel-Bided, 

 twice the length of the basals, and each about equally divided into body and limbs; 

 interradial sutures comparatively straight, placed in depressions; sinuses narrow and 

 snblinear ; lips slightly projecting. Ambulacra slanting sharply down from the 

 summit, and gradually decreasing in width ; side plates at least twenty-five in number 

 on each side, projecting above the margins of the sinuses. Deltoid plates exceedingly 

 minute, and quite apical. Hydrospires, spiracles, column, and ornament unknown. 



Remarks. The elongated form of the calyx in this species seems to us to leave little 

 room for doubt that it is one of the Troostoblastidie ; and we have referred it to 

 Metablastus rather than to Troostocrinus, under which name we originally described 

 it on account of its tendency towards a trihedral base. At the same time we are 

 quite prepared to admit that, when its summit characters are fully known, it may 

 turn out to be nothing more than a much elongated form of Pentremitidea, standing 

 in the same relation to some varieties of P. clavata (PI. V. fig. 17) as Pentrernites 

 clavatus, Hambach, bears to P. piriformis, Say. It is a much more robust species 

 than Troostocrinus Beinwardti, having larger, wider, and more expanding ambulacra 

 than are characteristic of that form (PL XII. fig. 11). The summit is also more 

 spacious and more truncated than the corresponding part of T. Beinwardti. The 

 Spanish fossil may be distinguished from J/, bipyramidalis, Hall, sp., by its shorter 

 ambulacra and fewer side plates, together with the greater elongation of the calj x 

 from the radial lips downwards. The proportions of T. Grosveuori, Shumard, are 

 also quite different from those of M. Hispanicus. Perhaps, on the whole, the latter 

 agrees better with M, Wbrtheni, Hall, sp., than with any of the species just named, 

 except that its ambulacra are broader. They are relatively longer than those of 

 Pentrernites subct/lindrica, Hall & Whit., and the radial angles are very different 

 in the two forms, while the long radials of M. lineatus, Shum., sp., are sufficient to 

 distinguish it from 31. Hispanicm. In the form of the radial plates, the relatively 

 broad ambulacra, and the cone-like base, the latter exhibits a resemblance to 

 Pentrernites clavatus, Hambach ; but we much doubt whether the summit structure 

 be the same in the two species. 



Locality and Horizon. Colle, near Sabero, Province of Leon, Spain : Calcaire 

 dArnao, Low T er Devonian. (Presented by Dr. P. H. Carpenter, F.R.S.) 



Metablastus Cottaldi, Mun.-Chalmas, sp. 

 (PI. V. fig. 22.) 

 Belemnocrinus Cottaldi, Mun.-Chalmas (MS.), Journ. Conchy 1. 1876, tome xvi. p. 105. 

 Belocrinus Cottaldi, Mun.-Chalmas (MS.), Bull. Soc. Geol. France, 1881, tome ix. no. 6, 



p. f)03. 

 Belocrinus Cottaldi, CEhlert, ibid. 1882, tome x. p. 362, t. 9. f. 3, a-e. 



2 D 



