286 Annals of the South African Museum. 



It is obvious that exigua, dijscrita, cakarata and gunnii are closely 

 related forms which need much more careful comparative study 

 than has been possible as yet. It is by no means clear how a 

 6-rayed individual of calcarata is to be distinguished from gunnii. 



ASTERINA LUDERITZIANA. 



Doderlein, 1908. Jahrb. Nass. Ver. Naturk. Wiesbaden, Jhrg. 61, 



p. 296; pi. 2. 



This well-characterized species is represented in the present col- 

 lection by two specimens from Walfish Bay, some distance north of 

 the type-locality at Angra Pequena. 



ASTERINA GRACILISPINA *, sp. nov. 

 Plate XVI. Figs. 3, 4. 



R = 6 mm.; r^4 mm.; R = l'5r. ; v. d. = 2'75 mm. Rays 5. 

 Abactinal plates arranged in half a dozen distinctly imbricating series 

 on each ray and a few additional plates at the interradial margin; 

 secondary plates few and confined to center of disk. Each abacti- 

 nal plate has the free surface covered with well-spaced minute, 

 short, sharp spinelets. Papulae rather large, in about eight series 

 on each ray but many series are very incomplete. Seen from above 

 there is no evident marginal fringe of spinelets. No madreporite 

 can be seen. 



Actinal intermediate plates not very numerous, 50-60 in each 

 interradial area, but most of these are small plates near the margin; 

 each plate carries a single transverse series of 3-5 delicate spinelets, 

 of which the middle ones are longest; those near mouth are *40 

 mm. long but they become smaller and smaller as the disk margin 

 is approached. In many series the spinelets appear united by 

 a web. 



Adambulacral armature in two series, as usual; the furrow series 

 is made up of 3 or 4 slender, pointed spinelets, the middle ones 

 half a millimeter long, united by a web; the series on the actinal 

 surface of the plate is similar but is placed obliquely or almost 

 directly at right angles to the furrow margin ; there are rarely, if 

 ever, more than three spinelets in this series and they are smaller 

 than the furrow series. 



Oral plates, each with five spines on the free margin and two 

 spines on the actinal surface; of the marginal spines, the proximal 

 two are large and flat, somewhat truncate while the other three 



* gracilis = delicate -j- spina = spines, in reference to the. delicate spinulation. 



