Note on Loveri 's Article on '* Leskia m irabti is. Gray." 245 



anus, if the calyx and arms alone were found fossil. This seems 

 so natural an explanation, so entirely in accordance with all we 

 know of the anatomy of Echinodcrms, that the mouth should be 

 somewhere along the ambulacral furrows, at their junction, 

 where the annular ambulacral tube is placed, but that junc- 

 tion need not necessarily be a central point of the disc, that I 

 give it for what it may be worth, loath as I am to assume the 

 correctness of a theory which would place the mouth outside 

 of all connection with the ambulacral furrows, a supposition 

 totally unsupported by all homological inferences to be drawn 

 from living Echinoderms. Nor can we suppose that this connec- 

 tion between the mouth and the ambulacra can have been sepa- 

 rated inCrinoids, because we find one opening performing some- 

 times the functions of both mouth and anus. In the recent 

 Echinoderms in which this is the case, we find that the opening 

 performing this double function is invariably the mouth, which 

 is placed at the point of confluence of the ambulacra. 



The whole history of the embryological development of Cri- 

 noids, which is sufficiently well known for our purposes, shows 

 us that such a separation between the mouth and ambulacra 

 never exists in any of the earlier stages, and any theory which at- 

 tempts to explain the homology of Crinoids on the assumption 

 of the separation of the ambulacral system from the mouth, must 

 explain away all we know of the anatomy of Echinoderms, and 

 all we know of their development; it is contrary to everything 

 we find in the living types, which after all must be our guid 

 and a theory against which such a sweeping assertion can 

 substantiated must be based upon an incorrect interpretation of 

 the facts observed in their old fossil representatives, which cer- 

 tainly have not been built upon a type differing from that of 

 their representatives of the present day. 



