180 CATALOGUE OF THE BLASTOIDEA. 



Pentremitidea angulata, E. & 0. 

 (PI. IV. figs. 13, 14, 1G.) 



Pentremitidea angulata, E. & C, Ann. & Mag. Nat. Hist. 1882, vol. ix. p. 224. 



Sp. Char. Calyx pentagonal-obpyriform ; summit small; section decagonal above, 

 without reentering angles between the ambulacra, but triangular at the base ; 

 periphery equatorial. Basal plates a little less than half the length of the radials, 

 forming a strongly trihedral cup, with three prominent angles, one interradial and 

 the two others radial ; surface of the plates between the angles hollowed out. 

 Radial plates elongate, their surfaces in two planes, which cut one another at the 

 equatorial line of the calyx ; the upper, sloping away to the summit, consists of the 

 limbs ; the lower, or the body below the lips, extends to the basiradial sutures and 

 is hollowed out on each side, a median ridge passing downwards from the lips to 

 the basiradial sutures, whilst the angle produced by the union of the two planes 

 forms the periphery or equator of the calyx ; interradial sutures not placed in 

 depressions but forming the five additional angles of the calyx ; sinuses narrow and 

 long, their distal extremities being equatorial ; lips prominent. Deltoid plates quite 

 apical. Ambulacra rather long and very narrow, maintaining almost the same 

 width throughout their whole course ; lancet-plates nearly as wide as the sinuses 

 and partially visible in the middle line ; side plates about twenty in number on each 

 side of an ambulacrum, short but broad. Spiracles close round the mouth ; anal 

 spiracle with a prominent outer margin. Ornament of fine lines parallel to the 

 margins of the plates. Column unknown. 



Remarks. This is a very interesting and peculiar species, and represents together with 

 that next to be described one extreme type of the genus. The form of the calyx, 

 and the angulation of the radial plates will readily separate P. angulata from all the 

 described species. The abruptly clavate outline indicates an approach to P. clavata, 

 Schultze, sp. (PI. IV. fig. 18) ; but no other resemblance is observable ; whilst with 

 P. similis, nobis (PI. X. fig. 2), although after the same general type, no definite 

 comparison can be made, as the latter has a longer and more tapering base, and 

 hollow interradial areas. There is a curious resemblance in external form between 

 Pentremitidea angulata and Pha'nosehisma caryophyllatum, de Kon. & le Hon, sp. 

 (PI. XIV. fig. 4), a member of a distinct genus that differs altogether from Pentre- 

 mitidea in its other characters. Pentremitidea angulata is the aberrant species of 

 the one genus as Phcenoschisma caryophyllatum is of the other. Both agree to a 

 certain extent in outward form, and differ in this particular from the other species of 

 their respective genera. 



Locality and Horizon. 1 Ferroiies, Province of Asturias, Spain : Lower Devonian. 



Pentremitidea similis, K. £ C. 

 (PI. V. fig. 16 ; PI. X. tigs. 1-3.) 

 Pentremitidea similis, E. & C, Ann. & Mag. Nat. I list. 1SS2, vol. ix. p. 225. 

 Sp. Char. Calyx pentagonal-obpyriform, expanding rapidly upwards above the 



