Common Starjisli. 225 



may be so numerous in this species as to give the surface a 

 villous ai:»pearance. 



III. Left radius of trivium. The two digestive eoeca have been 

 displaced from their normal connections within the cavity 

 of the ray, and are displayed in the interradial space on 

 either side. Towards the apex of the ray are seen the 

 ambulacral ampullae belonging to one of the two biserial 

 rows of locomotor feet, in the middle line are seen the 

 ambulacral ossicles, and on either side the generative glands, 



IV and V. Left and right rays of bivium. The gi*eater part of 

 the digestive and reproductive organs have been removed, 

 and the ambulacral ampullae, d 2, forming four rows, corre- 

 sponding to the two rows of sucker-like feet arranged on 

 either side of the ventrally-placed ambulacral furrows, are 

 seen on either side of the middle line occupied by the mesial 

 articulations of the successive pairs of ' vertebral^ or ' ambu- 

 laeraP ossicles, ki, ka. Externally on either side to the 

 rows of ampullae, are shown diagrammatically the more or 

 less regularly quadrangular reticulations, formed by the 

 ' interambulacraF ossicles. Of these interambulaeral ossicles, 

 there are in this species eight rows, interposed between the 

 ambulacral ossicles and the less regularly disposed ' tergal ' 

 ossicles. Of the interambulaeral rows, the first, third, and 

 sixth carry spines on their ventral surfaces ; the second, 

 fourth, fifth, seventh and eighth are devoid of them, and 

 act simply as commissural bars uniting the whole series 

 into a quadrangularly reticulate skeleton. Of the tergal 

 ossicles, some are spinigerous and some simply connective ; 

 the ambulacral never carry spines. 



a. Intestinal cavity, communicating freely with the stomach 

 proper, seen below at c, and giving off a stem which bifurcates 

 as it enters each ray. 



6 I . One of the arborescent divisions into which the radial diver- 

 ticulum of radius I divides. It is only in the Asteriae that 

 this digestive tract has this radial arrangement of digestive 

 or 'hepatic' coeca. 



Q 



