220 Natural-Historical Collections. 
He found this species of worm on the Octopus granulatus, (Lamk.) Neither. 
the. O. communis nor the Eledona, nor any other of the Cephalopoda furnished 
it, notwithstanding the trouble which he took in examining them for this pur- 
pose ; so that the hecatoncotylus seems. to be peculiar to the O. granulatus. - 
Of five individuals which fell into the hands of M. Laurillard, three were in 
the bag of a single Octopus, their heads being attached to some point of its inte- 
rior, and the tails allongated into the abdominal sac, but without penetrating the 
peritoneum. A fourth was in another animal, but in a similar position. The 
fifth alone was attached, as we have said, to the arm of an Octopus, and had 
transformed it into a kind of pouch, where it had introduced its head, the rest of 
the body hanging unattached externally. The hecatoncotylus is, then, properly 
speaking but semi-intestinal, or rather semi-externally parasitical, like the poly- 
stoma, tristoma, and like the lernea, and chondrecanthus. It detaches itself 
easily from the animal upon which it lives, and commits itself to the waters of 
the sea, or mounts the solid rock, without appearing to suffer much inconvenience 
from these changes of position ; it attaches itself closely, by means of its suckers, 
to the fingers or to any other body, imitating in this respect its patronal Octopus, 
for that is the term by which we must designate an animal which a parasite de- 
vours. 
M. Cuvier gives the following anatomical description of this animal. Its form 
is elongated, and somewhat prismatic, its dorsal surface being rounded, and the 
inferior a plane. The ordinary length is from four to five inches. It is thicker 
and more elevated anteriorly, where its breadth is from four to five lines, and its 
height from six to seven ; each of these dimensions gradually diminish posteriorly, 
but especially the height, which is reduced to less than a line, whilst its breadth 
is still two lines ; the anterior extremity is obtuse. But we cannot follow the 
author through his anatomical details. The suckers are placed on the external 
surface ; fifty-two pairs may be counted. M. Cuvier then describes the stomach, 
intestines, and alimentary orifice which appears to be unique in this animal. He 
passes next toa very remarkable apparatus, which he supposes to be connected with 
generation. This organ, whose functions still remain to be determined in a pre- 
cise manner, will offer a curious subject of research to those naturalists who may 
have an opportunity of examining the living hecatoncotylus.—Le Globe. 
To the Editors of the Edinburgh Journal of Natural and Geographical Science. 
GENTLEMEN,—I beg leave to send you some extracts, from a letter I have 
received from Mr. Kenyon, in answer to my observations on his paper, which ap- 
peared in your Journal for October last, page 65. I am gentlemen, your obedient 
servant, Tuos. Brown. 
Valvata piscinalis. Your remarks on this shell are doubtless correct. I be- 
lieve the V. planorbis of Drapernaud, is the V. cristata of Fleming. Draper- 
naud’s V. spinorbis, (spelt V. assiorbis, in the Magazine of Natural History, by 
the printers mistake), is not British ; and the V. minuta, is Dr. Turton’s Turbo 
serpuloides, according to the latter observations, in a letter to me, by my friends. 
Lymnea fragilis. When I first sent the paper for insertion, to the Magazine 
of Natural History, it was not my design to have it illustrated by any figures. 
Mr. J. D. C. Sowerby, however, addressed a letter to me, informing me, that it 
was the Editor’s wish, as much as possible, to give figures of the subjects of which 
scientific names were used, and stated, that he had in the museum of his late 
father, (James Sowerby,) most of the species I had mentioned, but there were a 
few others, he observed, which might not be the same shells, as those I had 
mentioned under the same names, and he particularly requested me to send him 
specimens of Valvata piscinalis, large and small, Lymnea ovata, Helix hispida, 
