the Morpliology of the Blastoiclea. 223 



cles. They are visible in P. lusitanica^ and again in P. 

 SchuUzn, but are of a much more elongated form in the latter 

 speeies. 



The species we propose to place in Pentremitidea are the 

 following : — 



Pentremites Pailletti, d'Orb. Devonian ; Astm-ias. 



P. Schultzii, d'Orb. Ditto. 



P. acutangulus, Schultze. Devonian ; Eifel. 



P. clavatus, Schultze. Ditto. 



P. eifelensis, F. Romer. Ditto. 



Pentrenntidea lusitanica, nobis. Devonian ; Spain 



(? Asturias). 

 P. angidata^ nobis. Ditto. 

 P. similis, nobis. Devonian ; Eifel. 



Pentremitidea appears to be essentially a Devonian genus, 

 being altogether unrepresented in the Carboniferous rocks. 

 Half its known species occur in the Eifel, and the rest 

 in the Asturias. The fine collection of Mr. Wachsmuth 

 contains an unnamed Blastoid from the Upper Silurian or 

 Lower Devonian of Charleston, Indiana, which we cannot 

 distinguish from the Spanish Pentremitidea PaiUetti. So far 

 as we know at present, tliis is the only species of Blastoid 

 which is common to Europe and America. We think it 

 very probable that some of the more obscure American species 

 of Peiitremites Avill also have to be referred to this genus. 



Pentremitidea lusitanica^ sp. nov. 



Sj). char. Calyx clavate-pyriform, elongated, expanding 

 gradually upwards ; peristome truncate ; base elongate and 

 pointed. Basal plates only a trifle shorter than the radials, 

 forming an elongated cup, the lower portion of each plate 

 bearing a strong central ridge, Avhich assists in the ornamen- 

 tation. Eadial plates rather narrow, elongated, and arched 

 from the lip downwards along the body. Three impressed 

 lines diverge from the lip, one to each infero-lateral ano-le 

 and one along the middle line. Kadial sinuses with sharp 

 erect margins, making an angle of about 134° with the trun- 

 cated peristome ; lips a little thickened and simply rounded. 

 Ambulacra elongately petaloid ; lancet-plates broad, almost 

 wholly filling up the radial sinuses ; side plates large and 

 oblong, their outer margins rounded, a1)out fifteen in number 

 on each side the ambulacra ; outer side plates narrow, bent 

 down at a much greater angle tlian the side plates. Surfjice 

 ornamented by fine close concentric raised lines parallel to the 



