274 CATALOGUE OF THE BLASTOIDEA. 



outer side plates very small and triangular. Hydrospire-slits from twelve to eighteen, 

 crowded together. Mouth small ; anus roundly triangular. Surface ornamented by 

 sharp strife parallel to the margins of the plates ; a distinct border follows the margin 

 of each radial plate, defined by a faint groove. 



Remarks. Phcenoschisma Verneuili needs no comparison with other species of the 

 genus, except with P. acutum (PL XIV. fig. 10), from which it differs in size, in the 

 elevated nature of its interradii, and in its greater number of hydrospire-slits. As 

 regards form, P. Verneuili represents one extreme modification of the genus, and 

 P. caryophyUatum another (PI XIV. fig. 4). 



Localities and Horizon. Ferrones, Province of Asturias, Spain : Calcaire de Ferrones, 

 Lower Devonian. [Also at Colle, near Sabero, Province of Leon : Calcaire d'Arnao.] 



Ph/enoschisma Archiaci, E. & C. 

 (PL XL fig. 7 ; PL XII. fig. 10 ; PL XIV. figs. 5-7 ; PL XVII. fig. 15.) 

 Pentremitidea PaiUeti (pars), Carpenter (non Verneuil), Report, Brit. Assoc, for 1881 



[1882], pt. 2, p. 634. 

 Phcenoschisma Archiaci, E. & C, Ann. & Mag. Nat. Hist. 1882, vol. ix. p. 230. 



Sp. Char. Calyx clavate, becoming more pentalobate with age ; sides concave, not 

 straight ; base long and often sharp ; summit truncate. Basal plates very long and 

 slender, longer than the radials, and expanding very gradually into a small cup, the 

 surfaces ornamented with concentric striae which have two different directions, while 

 the lower part of each plate bears a strong median ridge. Radial plates small, lobate 

 about the lips, projecting somewhat upward, and obliquely truncate on their upper 

 margins ; those of the anal interradius are a little flattened ; surface somewhat 

 angular in the middle line from the lips down to the basiradial suture ; sinuses 

 short, having a radial angle of about 130°, and somewhat petaloid. Deltoid plates 

 much overlapped by the radials and confined to the immediate neighbourhood of the 

 mouth. Ambulacra short, and a little petaloid; lancet-plates narrow, deeply tri- 

 angular in section ; side plates few, six to eight or nine, large and oblong ; outer 

 side plates triangular, and very small. Hydrospire-slits six to eight on each side of 

 an ambulacrum, the innermost one covered by the lancet-plate, a limited number only 

 being exposed when the side plates are in position. Hydrospires in the form of long 

 slender sacs. Mouth small. Anus roundly triangular. Column composed of round, 

 apparently biconcave, and for the size of the calyx, thick joints; canal very minute. 

 Ornament of concentric stria?. 



Remarks. This is a common species and has been very generally confounded with 

 Pentremitidea Paillettei, several examples of it having been found under this name 

 in the National Collection mixed up with others which are really referable to that 

 species. It is, however, an entirely different type. For apart from the direct ex- 

 posure of some of the hydrospire-slits, its ambulacra are altogether different from 



