Experiments on the Respiration of Melampus. 287 
be drawn from the preceding experiments, on the other side. Yet it 
may not be amiss briefly to recapitulate them, putting against each its 
contradictions, to set the matter in its clearest light. 
The arguments tending to prove Melampus to belong to the Pulmonea 
or air-breathing Mollusca, are, 
1. The habits of Mel. equalis (Experiments 1 and 2.) are not what 
we should imagine to be those of a marine Pectinibranchia, living 
habitually in water. 
Rendered inconclusive by the habits of Littorina vulgaris and other 
littoral Mollusca, decided Pectinibranchia, which are exactly the same. 
And Melampus exiquus has not these habits (Experiments 5, 6.) but re- 
mains at the bottom of the water. 
2. Its surviving for six weeks in a box without water (Experiment 4.) 
But it was in wet sponge; and besides, Littorina vulgaris, im the 
same box, did also survive. At all events, the anomaly is not greater 
than in the case of Truncatella truncatula. See Experiments 16 and 17. 
3. Its not living more than 3—4 days immersed in sea-water. 
Surely 3—4 days are enough, comparing it with the'time that a Helix 
survives (see the two. preceding notes ;) but if not, seven out of eight 
specimens of Pedipes afra (a decided Pectinibranchia) survived no 
longer ; the eighth lived two months immersed ! 
4. Its pectinated branchie are not visible. _ 
But the small size of the species, not to mention’ want of instruments 
and skill in the dissector, sufficiently explains this. 
5. The presence of the bubble of air at the mouth of the orifice in 
the mantle, &c. 
This is caused only by the air accidentally received into the cavity of 
the shell, and amongst the branchi@, when the animal has been some time 
out of the water; and besides, in Melampus exiguus, it is not constant ; 
compare Experiments 6 and 7 with 5. 
The following are the recent species which appear to unite generically 
under Melampus as above defined. 
