26 s. goto: 



Sladen's description is as follows ['89, p. 7] : 



" Pararchaster scmisquamcihi.s, u. sp. (PI. II. figs. 1 and 2 ; PI. IX. figs. 

 7 and 8). 



" Raj's five. R^lßO mm. ; r = 15 mm. 11 = 11 r. Breadtli of a ray near 

 the base, 14.5 mm. 



" Rays very elongate, comparatively naiTow and flat, tapering gradually 

 and slowly from the base to the extremity, the onter part being very at- 

 tenuate. Disk very small. Abactinal sm-face plane, feebly convex or sub- 

 carinate along the median line of the rays. Lateral walls of the ray low 

 and vertical. Actinal sm-face of the disk prominent at the month-angles, 

 and sloping thence to the margin and very slightly along the rays. Inter- 

 bracliial arcs widely rounded. 



" The al)aetinal surface of the disk and rays is covered with small, 

 uniform, subcircular scale-like x^lî^-^s, which are overlaid with a delicate 

 memln'anous tissue. The x^Lates bear on their centime a single minute sub- 

 conical or cylindrical spinelet ; along the rays these are quite microscopic 

 thornlets, but upon the disk and at the base of the rays there are a number 

 of much larger spinelets ; the largest are elongate, about 7 to 8 mm. in 

 length, robust, tapering, and sharply ^winted, and their jx)sition probably 

 marks the primary apical plates ; the primary radiais and basais being 

 especially- distinguishable, and perhaps also the dorso-central and the under- 

 basals ; other spinelets rather smaller are present in the vicinity of these, 

 but they rapidly decrease in size as they recede from the central area ; and 

 really definite spinelets do not extend further along the base of the ray 

 tlrnu the third or fom-th supero-marginal plate. 



" Tlie supero-marginal plates, fifty-fi^'e in munber from the median 

 interradial line to the extremit}', are elongate and suboval in form, and are 

 confined entirely to the lateral wall of the ray ; their posture ap^jears slight- 

 ly oblique when viewed from the side, the aboral end of one plate standing 

 over the adorai end of the next outward ; their height is less tlmn half their 

 length ; and the upper margin of the plate forms the boundary of the 

 abactinal sm-face of the ray. On the centre of each plate is a large well- 

 defined tubercle, on which is articulated a rol)ust, cylindrical, tapering spine^ 



