the Morphology of the Biastoidea. 229 



We propose to include the following species in the genus 

 Phenoschisma : — 



Pentremites acutus, Phillips. Carboniferous Limestone, 



England. 

 Pentremites carj/ophi/llatiis^ de Koninck. Carboniferous 



Limestone, Belgium. 

 Phxenoschisina VerneuUi, nobis. Devonian, Spain. 

 Phcenoschisma Archiaci^ nobis. Devonian, Spain. 



Our researches have not disclosed the existence of the 

 genus during Silurian times ; but it appears to have made its 

 first ap])earance during the Devonian period, as represented 

 bj the Devonian rocks of Asturias, Spain. Phmaoschisma 

 reapjjears in the Carboniferous Limestone of England and 

 Belgium, but, so far as we can ascertain, is unrepresented in 

 the American PaUeozoic rocks, unless Pentremites hentucki- 

 ensis, Shumard *, from the Subcarboniferous rocks near 

 Louisville, Kentucky, be referable to this interesting tjpe. 



Phcenoschisma Verneuilij sp. nov. 



Sj). char. Calyx elongately pyramidal, with a sharp- 

 pointed base and a hollow sunnnit excavated in the direction 

 of the rays. The ambulacra are separated by strong inter- 

 radial processes, each of which is formed by the union of the 

 adjacent limbs of two contiguous radials. Section distinctly 

 pentagonal at the distal ends of the ambulacra. Basal plates 

 forming an elongated cup about two thirds the length of the 

 radials and a little longer than the bodies of those plates. 

 Radial plates large, arched, with prominent lips, from which 

 three folds diverge downwards ; limbs long and projecting 

 above the summit, except the two contiguous ones forming 

 the anal interradius, which are flattened or depressed ; sinuses 

 very wide and deep, with high sloping sides. The four 

 similar oral plates very small, but the anal-oral larger and 

 diamond-shaped. Ambulacra linear, scarcely increasing in 

 width ; lancet-plate narrow, entirely concealed ; outer side- 

 plates very small and triangular ; side plates from twenty to 

 twenty-five, apparently oblong ; liydrospire-slits from twelve 

 to eighteen, crowded together. Mouth small ; anus roundly 

 triangular. Surface ornamented by sharp striaj parallel to 

 the margins of the plates. A distinct border follows the 

 margin of each radial plate, defined by a faint groove. 



Obs. Phatnoschisma Verneuili needs no comparison with 

 other species of the genus, except with Ph. acutuni^ Phill. sp., 

 * Trans. St. Louis Acad. i. p. 239, t. Ix. f. 13. 



Ann. & Mag. N. Hist. Ser. 5. Vol. ix. 17 



