REPORT ON THE ASTEROIDEA. 



Chorological Synopsis of the Species. 



1. Pararchaster semisquamatus, n. sp. (PI. II. figs. 1 and 2; PI. IV. figs. 7 and 8). 



Pays five. R = 166 mm. ; r = 15 mm. R = 11 r. Breadth of a ray near the base, 

 14*5 mm. 



Rays very elongate, comparatively narrow and flat, tapering gradually and slowly 

 from the base to the extremity, the outer part being very attenuate. Disk very small. 

 Abactinal surface plane, feebly convex or subcarinate along the median line of the rays. 

 Lateral walls of the ray low and vertical. Actinal surface of the disk prominent at the 

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

 brachial arcs widely rounded. 



The abactinal surface of the disk and rays is covered with small, uniform, subcircular 

 scale-like plates, which are overlaid with a delicate membranous tissue. The plates bear 

 on their centre a single minute subconical 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 pointed, and their position probably marks the primary 

 apical plates ; the primary radials and basals 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 than 

 the third or fourth supero-marginal plate. 



The supero-marginal plates, fifty-five in number from the median interradial line to 

 the extremity, are elongate and suboval in form, and are confined entirely to the lateral 

 wall of the ray ; their posture appears slightly oblique when viewed from the side, the 

 aboral end of one plate standing over the adoral end of the next outward ; their height is 



1 The exact station off the coast of Portugal is not recorded. 



2 It is uncertain whether this species is from Station 44 or Station 45. 



