208 I. IJIMA : HEXACTINELLIDA. I. 



Whereas, all other specimens before rae (exceptuig one doubtful 

 case with much abraded surfaces) show a greater or less number 

 of ridge-like prominences or ledges, such as are fairly well 

 exemplified in PI. VI, figs. 1-3. Even the smallest specimen 

 (.4) exhibits a decidedly uneven surface, somewhat as in Pi. IV, 

 fig. 9. The ledges in the larger specimens may be 5 mm. high 

 but are more usually much lower. Their free edge may be said 

 to be tolerably even ; it is either blunt or sharp. In length the 

 ledges are quite indefinite, often rather short. They run in the 

 usual, irregular manner, but generally in either transverse or 

 oblique directions. 



In a certain specimen (Spec. /) I have found the ledges 

 for the most part somewhat unusually sharp-edged and supplied 

 along the edge with an inconspicuous, palisade-like row of 

 spicules, projecting to a length of about half a millimeter. In 

 the case of the more blunt-edged ledges of the same specimen 

 this palisade was wanting. Nor have I noticed it on any ledges 

 in all the rest of my specimens. On close observation it was 

 seen to consist of spicules similar to those which were likewise 

 inconstantly found on the sharper-edged lappets of E. mar- 

 shalli (p. 97). 



The cuff is on the whole inconspicuous, especially so in the 

 smaller specimens. It is quite usual that different parts of the 

 sieve-plate circumference show the cuff in different states of 

 development. It may in places even be wholly wanting. In its 

 highest development, the breadth does not exceed 4 mm., as 

 measured on the upper surface. It is of moderate thickness and 

 sharp-edged, being directed either outwards or more or less up- 

 wards. Generally there exists no spicular fringe along the edge ; 



