528 The Blennies: Blenniide 
the interior of which is coated over with mucus. There are 
no secretory glands embedded between these membranes, and 
these sacs are probably merely the reservoirs in which the fluid 
secreted accumulates. The absence of a secretory organ in 
the immediate neighborhood of the reservoirs (an organ the 
size of which would be in accordance with the quantity of fluid 
secreted), the diversity of the osseous spines which have been 
modified into poison organs, and the actual communication 
indicated by the foramen in the sac lead me to the opinion 
that the organ of secretion is either that system of muciferous 
channels which is found in nearly the whole class of fishes, and 
the secretion of which has poisonous qualities in a few of them, 
or at least an independent portion of it. This description was 
made from the first example; through the kindness of Captain 
Dow I received two other specimens, and in the hope of proving 
the connection of the poison bags with the lateral-line system, 
I asked Dr. Pettigrew, of the Royal College of Surgeons, a 
gentleman whose great skill has enriched that collection with 
a series of the most admirable anatomical preparations, to lend 
me his assistance in injecting the canals. The injection of the 
bags through the opening of the spine was easily accomplished; 
but we failed to drive the fluid beyond the bag or to fill with 
it any other part of the system of muciferous channels. This, 
however, does not disprove the connection of the poison bags 
with that system, inasmuch as it became apparent that if there 
be minute openings they are so contracted by the action of the 
spirit in which the specimens were preserved as to be impassa- 
ble to the fluid of injection. A great part of the lateral-line 
system consists of open canals; however, on some parts of the 
body, these canals are entirely covered by the skin; thus, for 
instance, the open lateral line ceases apparently in the supra- 
scapular region, being continued in the parietal region. We 
could not discover any trace of an opening by which the open 
canal leads to below the skin; yet we could distinctly trace the 
existence of the continuation of the canal by a depressed line, 
so that it is quite evident that such openings do exist, although 
they may be passable only in fresh specimens. Thus likewise 
the existence of openings in the bags, as I believed to have found 
in the first specimen dissected, may be proved by examination 
