OF CONCHOLOGY. 



59 



and how are these muscles attached ? Homologies and muscles 

 alike fail in such an emergency ! 



Prof. Morse likewise remarks that " Sipunculus and its allies 

 claim it as a right to have an anterior termination to their in- 

 testine." I do not dispute their right, but it is very evident, 

 from my preceding remarks on this subject, that they are very 

 far from attempting to exercise it, on many occasions. 



The other points brought up by Prof. Morse have been met 

 incidentally or directly in the preceding observations. 



The reader who has taken the trouble to follow out this train 

 of reasoning will observe that there is not a single character of 

 class or ordinal importance among those which Prof. Morse has 

 brought forward. Most of them are histological and doubtful, 

 and the sum of the whole may be comprised in the setae and the 

 oviducts. These have swollen to undue importance in his eyes, 

 as has been already shown — and per se are not of much syste- 

 matic value. 



The following tabular comparison will illustrate the differences 

 in the characters of real value in the several forms : 



SYNOPTICAL COMPARISON. 



The annexed homological diagrams will illustrate the princi- 

 ples under discussion. 



