OF WESTERN SIND. 49 



simple vertical series. The pores are round, conjugate, close; and close above and 

 below, the pairs being separated by a ridge with a very small tubercle upon it. The 

 composition of the ambulacral plate is interesting. The lowest or most adoral of its 

 poriferous plates usually extends the whole breadth of the ambulacral plate, as a band- 

 like strip of uniform thickness ; the next panr of pores is borne on the primary ambu- 

 lacral plate ; and the succeeding poriferous plates are small wedge-like plates for the 

 reception of which the primary ambulacral plate has its aboral and outer margin 

 scooped away, the aboralmost of these small plates not being more than one half the 

 breadth of the ambulacral plate, the intermediate ones smaller still. 



The ornamentation of the interporiferous zone is simple : there is a small primary 

 tubercle on each plate, placed nearer the poriferous zone than the median sutural line 

 from the actinostome to near, or midway to, the margin, where a second tubercle is 

 seen on two or three plates. The tubercles are small, nearly equal, and crenulate, 

 and their bases are flush with the test. A few very small tubercles, larger than 

 miliaries, are scattered without much order on the plates near the margin, and are still 

 nearer the peristome. 



The interradial areas are occupied by numerous low and broad plates, larger than 

 those of the ambulacra ; the median suture is well developed, and the other sutures 

 also, and they indicate some curving of the upper and lower margins of the plates. 

 The tubercles are small on the plates, equal to, if not slightly larger than those of the 

 ambulacra. On the actinal surface there is one primary tubercle on each plate near 

 the peristome ; a little further out there are two, and nearer the margin three, and 

 finally four to a plate. There are two vertical rows, which reach to the peristome on 

 each interradial area ; and then further out there are rows corresponding with the 

 increase in number of the tubercles. There are a few very small tubercles, and some 

 miliaries slightly smaller on the plates, and they are sparsely placed in more or less 

 concentric rows around the larger tubercles. 



Above the margin the number of larger tubercles can be estimated in spite of the 

 worn condition of the test, and two on each plate appears to be the number. The 

 smaller tubercles are larger there than on the actinal surface, and surround the larger 

 ones in a scrobicular circle, giving a granulated appearance. 

 The cuts for the branchiae are well developed. 



The length of the test is nearly 1-j^- inch, and the breadth is 2-j^ inch. 

 Locality. Ranikot series, north by east of Petiani, west of Kotri. Survey-number 



n- 2.8.0. 

 ^* 13 5' 



Illustrations of the Species in Plate VIII. 



Fig. 6. The outline of the test : natural size. 



7. The actinal surface : natural size. 



8. A part of the actinal surface : magnified. 



9. The cuts and the ambulacrum near the peristome. 



