PLATE XXVIII. 



Echinanthus rosaceus, 1, 2. 



1. Interior of test, the lower floor removed, j, /; pits upon which jaws articulate on 



the auricles ; /', line of junction of adjacent parts of pyramid ; o, o', o", o'", part of 

 ovaries which have been forced between the intestine and the jaws ; i', commence- 

 ment of intestine, passin;:; to i", then to i, i'", V^-, v", to the anal opening ; v, v, v", 

 main vessel following the course of the intestine. 



2. Abactinal floor removed, a v, ambulacral vessel ; v', vessel following the course of the 



intestine ; av to v, oesophagus ; i", i'", i'^; i, f, course of the intestine ; o, o, 

 o", o", o"^; ovaries ; j, f, line of junction of adjacent parts of the pyramid ; 

 P; P; P'> partition separating the intestinal cavity from the main actiual cavity. 



Cidaris tribuloides, 3, 4- 



3. Abactinal part of test and ovaries removed, a, anal opening ; i, i', i", i'", i'^-, 



intestine. 



4. Abactmal part of test removed, g, genital ring ; o, o', ovaries ; i, i', loops of intestiae. 



Ciadema setosum, 5. 



5. Section across equator showing abactinal part of interior, o, o, o", d" , o'^; d', d, 

 ovaries ; i, i', i", i'", i'^; abactinal loops of intestiue. 



Arbacia pustulosa, 6. 



6. Abactinal part of test and ovaries removed, j, jaws ; s, stone canal ; a, anal opening ; 

 i % , i", i'", loops of intestine. 



{Figs. 1, 2, tioo thirds natural size; Figs. 3-6, tiatural size.) 



The Drawings are made from preparations by A. AGASSIZ and N. BOWDITCH. 



