72 Couthouy’s New Species of Mollusca 
E. salmonacea, from which the drawing in the plate was 
made, which lived nearly a week, subsequent to being 
deprived of more than half the dorsal cirri. Individuals 
were, moreover, not unfrequently observed in situ, that 
had by some accident lost a portion of these organs. It 
is hardly probable that if they fulfilled the important vital 
functions ordinarily attributed to them, their loss could 
be sustained with such apparent impunity, or that they 
should be deranged or impaired from such trifling causes. 
If it be however actually the case, it must certainly be 
considered as at variance with all analogy, May not 
the organs of respiration themselves be internal, situate 
in the vicinity of the dorsal protuberance mentioned in 
the descriptions, and the cirri in some manner secondary 
or subservient tothem? The pulsation observed in that 
region, usually at the rate of sixty-five to seventy strokes 
per minute, had much more the appearance of respira- 
tory than arterial movement, being occasionally sus- 
pended for five or six seconds together, and recommenc- 
ing apparently at the will of the animal. Such an 
occurrence could not well be accounted for, if the pulsa- 
tions are referred to the motions of the heart; as the 
functions of that organ, being independent of volition, 
must, as in all other creatures, be performed with no 
other irregularity than that of occasional acceleration or 
retardation of the circulating fluid, produced by tem- 
porary disturbing causes. Unfortunately, at the time of 
observation, I was not in possession of any instruments 
sufficiently delicate for anatomical investigations of such 
animals; and after several clumsy trials with such as I 
bad, was compelled to relinquish the attempt. I would 
beg leave to direct the attention of the Society to this 
interesting point, and to express the earnest hope that 
