CHITONELLUS. 
Prats I, 
Genus CuitonrLivus, Lamarck. 
Testa octovalvis, valvis longitudinaliter oblongis, sejunctis, 
‘apophysibus valdé productis, medio pallii elongati in- 
crassati infivis, valvis antice apropinguantibus, postice 
remotis. 
Shell eight-valved, valves longitudinally oblong, isolated, 
with the apophyses very much produced, infixed along 
the middle of the mantle which is very thick and 
elongated, valves approximating anteriorly, remote 
posteriorly. 
The Chitonelli says M. Deshayes “differ in no respect 
from the Chitons, and the characters which serve to dis- 
tinguish them are so lightly estimated by naturalists, that 
they are only admitted by the majority as a subgenus or 
section of the parent genus.” The Chitonelli may resemble 
the Chitons in their internal organization, but in the con- 
dition of the mantle, the structure and disposition of the 
shell, and in habit, they differ materially. The mantle is 
very thick and fleshy, peculiarly elongated, sometimes 
covered with a harsh down, but mostly tough and leathery; 
it is invariably destitute of any horny cartilaginous part 
and is never furnished with any spines, bristles, or calcareous 
armature. The valves of the shell are of a longitudinally 
oblong form, with the inner posteriorly projecting plates 
or apophyses very much produced and firmly imbedded 
within the substance of the mantle; sustained by these 
alone they are perfectly isolated from one another, far 
removed posteriorly, but approximating towards the head, 
where they are often much crowded by the friction arising 
from the animal’s propensity for thrusting itself into holes 
and crevices. 
The Chitonelli are very singular in their habits and are 
rarely found to associate with Chitons; in Chili and along 
the whole south-west coast of America, abounding with 
that genus to the extent of some fifty or sixty species, not 
asingle Chitonellus is known to exist ; and in the Philippine 
Islands where there are but few Chitons, Mr. Cuming 
collected the C. fasciatus in plenty and of extraordinary 
dimensions. They were found dwelling in holes and cavities 
either of natural formation or bored by other mollusks, into 
which they force themselves by attenuating their bodies in 
a manner truly surprising. At the Island of Zebu, where 
Mr. Cuming collected a considerable number, they live 
partially or entirely imbedded in holes and circuitous 
crevices in the coral rocks, sometimes turning completely 
at right angles and at angles again; those that were only 
partially imbedded having attenuated and forced themselves 
into a smaller hole than was adequate to contain them, the 
posterior part of the body hung down fat and swollen, and 
invariably separated from the anterior half whenever any 
force was used to draw the animal from its hiding place. 
Mr. Cuming did not find the Chitonelli under any other 
circumstances, and could only obtain specimens entire by 
splitting the masses of coral in which they were imbedded, 
attenuated in many instances to a foot or more in length. 
Capt. Sir Edward Belcher, and his Assistant Surgeon, 
Mr. Adams, collected the same species of smaller size 
in the Korean Archipelago in the Yellow Sea; it was 
found by these zealous travellers in company with Chitons 
but noticed to be of locomotive habits; on lifting a stone 
to which a Chitonellus might be attached, it was observed 
to crawl away at about the pace of the common Garden 
Snail in search of retirement. 
Species 1. (Mus. Cuming.) 
CHITONELLUS La&vIS. Chit. testd valvis latiusculis, posticé 
productis, approximatis, undique reclinantibus, levibus, 
ad latera subtiliter granulatis ; albidd, rufo triradiaté ; 
pallio scabro. 
THE sMOOTH CHITONELLUS. Shell with the valves rather 
broad, produced, approximating, reclining one upon 
the other throughout, smooth, finely granulated at 
the sides; whitish, with three red rays, mantle rough, 
Lamarck, Anim. sans vert. (Deshayes’s edit.) vol. vii. 
p. 481. (not of De Blainville). 
Chitonellus strigatus, Sowerby. 
Hab. Australia. 
It is impossible to indentify Lamarck’s species of Chiton- 
ellus with any certainty, but this assuredly accords better 
with his description of C. /evis than any that I have met 
with. 
Species 2. (Fig. a and 6. Mus. Cuming.) 
CHITONELLUS FascraTus. Chit. testé valvis posticis remotis, 
oblongo-ovatis, concentricé sulcatis, anticis approximan- 
tibus, levibus ; lutescente-albidé rufo medio tinct ; 
pailio valde incrassato, elongato, tunudo, lutescente- 
viridi, fusco-nigricante varie fasciato. 
THE BANDED CHITONELLUS. Shell with the posterior valves 
remote, oblong-ovate, concentrically grooved, the an- 
terior approximating, smooth ; yellowish white, stained 
in the middle with red; mantle very thick, elon- 
gated, swollen, yellowish green variously banded with 
brownish black. 
Quoy and GarmarpD, ‘ Voy. de!’ Astrolabe,’ Zool. vol. iii. 
p. 408, pl. 73. f. 21 to 29. 
Chitonellus levis, De Blainville. 
Hab. Tonga-Taboo, Friendly Islands; Quoy and Gaimard. 
April, 1847. 
