286 Rev. II. T. Lowe on Melmnpus, 6;c. 



The foregoing experiments are set down in the order in which they 

 were made ; and it is possible that the former of them may at first lead 

 others, as they did myself, to different conclusions from those I am now 

 convinced are the true ones. At least, they might have been so arranged, 

 as to establish, in the first place, the fact attempted to be proved in the 

 mind of the reader, and to enlist first impressions on my side, were vic- 

 tory, not truth, the object. Yet, antecedent to all experiment, the fol- 

 lowing are strong arguments that Melampus aqualis and exiguus belong 

 to the Pectinibranchia. For, 



1. They are found on the sea-beach, between high and low water- 

 mark. 



2. In a state of nature they have the habits, and are found in the 

 company, of other undoubted marine Pectinibranchia, viz. Pedipes afra, 

 and Truncatdla truncatula. 



The positive arguments on the same side, to be deduced from the 

 foregoing experiments are, 



1. In confinement, one of the species remains voluntarily beneath 

 the surface ; the other has the habits of other littoral species, decided 

 Pectinibranchia, viz. Littorina vulgaris, Pedipes afra, &c. 



2. Melampus cequalis lives 3 — 4 days in apparently a healthy state, 

 immersed in sea-water, without coming in contact with the air.* 



3. But dies in a few hours, immersed in fresh-water.f 



I have before shown the inconclusiveness of any arguments that can 



* Two large and vigorous specimens of Helix lactea, from Grand Canaria, 

 placed in ^ea- water, immediately retreated deep within their shells, without an 

 attempt to extricate themselves, and never protruded themselves again. At 

 the end of eight hours they were quite dead. 



f Two fine and healthy specimens of the same Helix were inclosed in bags 

 and immersed in/re^A- water. At the end of six hours they were nearly dead, 

 and at the end of twenty-four completely so. Other smaller species do not 

 usually survive so long. 



