OF KACHH AND KATTYWAK. 43 



porite is minutely but distinctly and sharply granular, there being minute foramina in 

 the spaces between the granules. 



The anterior odd ambulacrum is in a groove which is very shallow and narrow at 

 first, and which increases in breadth and depth to the margin, which it excavates con- 

 siderably, and it is continued over, gradually diminishing, to the peristome. The pairs 

 of pores are only visible near the apical system, and are very small and distant. 



The antero-lateral ambulacra, rather sinuous, are in broad shallow grooves, which 

 gradually diminish in depth near the distal end of the ambulacrum. The ambulacra 

 are very wide apart, are petaloid near the apex, and open at the other end, which does not 

 extend to near the margin ; they are curved slightly near the apex, the convexity being 

 forwards, and more decided further out, where the curve alters in its direction and 

 the convexity looks forwards and inwards. 



The poriferous zones, which are well developed, are situated on the slopes of the 

 groove ; and the pairs of pores, small in size near the apex, increase suddenly in dimen- 

 sions. The zones increase in size about halfway to the end and then diminish, the ends 

 being rather narrow, but not coming to a point ; they show no tendency to close. The 

 pores are large, subequal, and are rather more elliptical than circular in outline ; they 

 are conjugate by a broad shallow groove, which is interrupted by a ridge which sur- 

 mounts the broad shallow costa between each pair. This ridge usually has from seven 

 to eight close granules in linear series on it, or some or all of the granules may 

 coalesce to form two or three in a broken line or a ridge. There are about 36 pairs 

 of pores in each poriferous zone. At the end of the poriferous zone the pores diminish 

 greatly in size, become very elongate, and are rare and distant. 



The interporiferous area is narrower than the poriferous zone, and it becomes 

 broader towards the end, where it equals the diminished zone in breadth. Its 

 ornamentation is scanty, and consists of a small tubercle which is placed at the 

 junction of the costa with the zone, and of small granules scattered very sparingly and 

 of about the same dimensions as those on the costge. 



The postero-lateral ambulacra form a small angle by their divergence, and are in 

 broad shallow grooves sloping rather on the sides of the posterior tumid interradium. 

 They are petaloid at the apex, are broad further off, and they retain their breadth 

 close to the end, which is remote from the margin, the only narrowing consisting of a 

 closer approach of the pores of the last four or five pairs. They are longer than the 

 antero-lateral ambulacra, about equal in breadth to them, and are slightly curved, the 

 concavity being directed forwards, outwards, and downwards. The poriferous zones have 

 about 42 pairs of pores, those nearest the apex being very small. The pores are subequal, 

 but towards the distal extremity of the ambulacrum the outer pores become more 

 elongate elliptical than the others ; at this part the pores become closer, and at the end 

 smaller. The interporiferous area is smaller than a poriferous zone, barely equalling 

 half its breadth. The greatest breadth of the ambulacra is 7 millim., and the length 

 of the antero-lateral is 35 millim., that of the postero-lateral being 43 millim. 



Actinally, the region of the postero-lateral ambulacra is broad, long, and nearly 



g2 



