E. MARSHALLI. — GEN. CHARACTERS. 



80 



Specimen G of the above list is about the largest specimen 

 of the species I have as yet met with. 



The body-wall measures not more than 3 mm, in thickness, 

 leaving the height of the parietal ledges out of consideration. 



The ratio of the body-length to the greatest breadth may 

 be put down as 1 : 0.3-0.44. In comparison with either E. imperialis 

 or E. oweni, the body is considerably shorter in relation to its 

 breadth. 



The parietal oscula, not over 2 mm. in diameter, are rather 

 irregularly scattered. They lie in broadly pit-like or elongate 

 valley-like depressions of the external surface, sometimes singly 

 and at other times in groups, but without a definite rule as to 

 their relative position. Those opening on the same depressed 

 area are separated from one another by an interspace which is 

 either gently convex or nearly flat and varies from 1 mm. to 



*The fluctuation of diameter in the same individual, to be noticed in this column, is 

 mainly due to the various degrees of tlie development of the parietal ledges at different 

 points of the circumference. Leaving aside these ledges, the cross-section of the body may 

 be said in general to be approximately circular. 



