694 RITTER. 



Some of the characters, such as the number of bars on or 

 between the folds and the number of the accessory languets, 

 are variable, but the variation seems to be in the direction of 

 increase of number with increase in the size of the individual. 



There are so many points in common between this species 

 and C. siipcrba that I have been in much doubt as to whether 

 they are not the same thing. It has seemed possible that the 

 smaller animals may be only immature individuals of the larger 

 one. I have tried to explain the differences between the two by 

 imagining them to be such as would be expected were this the 

 case ; but the explanations thus reached are unsatisfactory, as I 

 shall now attempt to show. 



In the first place, as regards the papillae on the surface of the 

 test. These are frequently single in C. snpcrda, while they are 

 never so in C. dcaiii ; again, when the large ones have smaller 

 ones about their bases, these smaller ones are always closer to 

 the larger, and less numerous in the former than in the latter 

 species. Compare figures i6 and 21, the first from the anterior 

 part of the body of C. siipcrba, the last from a corresponding 

 region of C. dcani. These differences I do not believe are 

 due to differences in age merely. One might imagine that the 

 condition seen in C. supcrba has been produced from that in 

 C. deani by an extension and thickening of the bases of the 

 primary papillae until they have come to carry the secondary 

 ones on their sides. As a matter of fact, however, the base of 

 a group, /. c, of a primary papilla with its surrounding secon- 

 dary ones, is actually somewhat larger on the average in C. dca?n, 

 the supposed younger specimens, than in C. supcrba. Thus 

 their average diameter at base is 1.9/^ in the former species, and 

 1.55 /^ in the latter, measurements being made of papillae from 

 near the anterior end of the animal in each case. 



As to external characters, it is to be further noted that C. 

 supcrba is much more highly colored than C. dca)n, the entire 

 anterior half of the former being orange red, while only the 

 siphons are red in the latter, and these not markedly so. As all 

 the specimens in this collection were preserved in the same way, 

 i. c, in formalin, it cannot be supposed that the color has been 



