172 s. goto: 



same length ; of the second pair the abcentral spine is almost 

 invariably much the larger of the two, and in a few cases there 

 w^ere three in a row instead of two, when the middle one was 

 the largest ; there may be a third pair and an odd spine or other 

 combinations which are shown by the preceding formula?. 



Mouth-plates. — When denuded of the spines, the mouth-plates 

 are very prominent, and are more pointed at the distal end (PI. Ill, 

 fig. 44, 45). There is a principal crest running through the entire 

 length, and an accessory ridge running up nearly half as far from 

 the proximal end. There are about eight or nine spines on the 

 principal crest, increasing in length towards the mouth, and about 

 six on the accessory ridge, which are also longer towards the 

 mouth. 



Ventrolaterals. — These are very small, and there are 1-2 on 

 either side of the interradial line (PI. Ill, fig. 44). They are 

 covered with spines similar to the smaller spines of the infero- 

 marginals. 



Paxillce. — The paxillar area at the middle of the arms is more 

 than twice as broad as the superomarginals of one side. There 

 is an area of small paxillos at the centre of the disk, which, 

 however, is not so very prominent or so large as in Astrop. scopa- 

 Q'ius (PI. Ill, fig. 42). The coronal spinelets are less numerous 

 and more divergent than in Astrop. scoparlus, there being some 

 27 or so in one of the largest paxilla3, which are usually found 

 at about the middle of the base of the arm (PL III, fig. 49). 

 The most striking difference in the paxillœ of this species, as 

 compared with Astrop. scopaiius, is, however, the fact that there 

 is not such a well marked difierence" between the centrals and 

 peripherals. All the spinelets look very similar to one another, 



