ASTACOLUS. 9 
ARGONAU’TA. Auct. Commonly called the Paper Sailor. 
Fam. Pteropoda, Bl Order. Cephalopoda Monothalamia, Lam. 
Deser. Light, thin, symmetrically convolute, carinated, concen- 
trically ribbed or tuberculated; aperture large, elongated; peri- 
treme simple, acute, interrupted by the body whorl. Obs. This 
elegant production of the Mediterranean and other Seas, is in- 
habited by a molluscous animal called the Ocythoe, provided with 
tuberculated arms, which, hanging over the sides of the aperture, 
give to the whole the appearance of a vessel propelled by oars; a 
poetical illusion, still further heightened by the broad flat mem- 
branes of two of the arms, which being spread vertically, present 
the idea of sails. Pliny has described it as sailing on the Mediter- 
ranean waters. Scientific men have long been engaged in the 
interesting discussion, whether the animal really belongs to the 
shell in which it is found, or whether, having destroyed the right- 
ful owner, it has possessed itself of the “frail bark.” A. Argo, 
fig. 485. 
ARTEMIS. See Venus. Ex. fig. 118. 
ARTICULATED. Jointed. Applied to distinct parts of shells, 
that are fitted or jointed into each other, as the valves of Chitones. 
The operculum of Nerita is articulated to the columella. 
ARTICULINA. D’Orb. A genus of microsopic Foraminifera. 
ASIPHONIBRANCHIA’TA. Bl. The second order of Para- 
cephalophora Dioica, Bl. Consisting of spiral univalves, which 
have no notch or canal at the anterior part of the aperture. This 
order is divided into families, Goniosomata, Cricosomata, Ellip- 
sostomata, Hemicyclostomata and Oxystomata. 
ASPERGIL'LUM. Lam. (From Aspergo, to sprinkle.) Fam. 
Tubicolz, Lam. Pyloridea, Bl. Descr. The small, equal, equi- 
lateral valves are cemented into, so as to form part of a large 
tube; the umbones are slightly prominent outside. The tube 
is elongated, rather irregular, granulated with sandy particles, 
and terminated at the base by a convex disc, which is perforated 
by small pores, elongated into tubes round the edge, presenting 
the appearance of the spout of a watering pot, whence the 
name is derived. Loc. New Holland, Java, New Zealand, Red 
Sea. Fig. 44. Aspergillum Vaginiferum. 
ASSIMIN’EA. Leach. Fam. Turbinacea, Lam. Descr. Inclin- 
ing to oval, light, thin, covered with a horny epidermis, spire 
produced into an acute pyramid; whorls slightly angulated in 
the centre, rounded beneath; aperture elliptical, slightly modi- 
fied by the last whorl; inner lip planed; outer lip thin. Found 
in brackish water; one species may be procured abundantly on 
the muddy shores of the Thames, in Kent. Without comparing 
the animals, it is difficult to distinguish this genus from some 
species of Littorina. Fig. 363.* A. Grayana. 
ASTACO'LUS. Montf. Microsopic. Cristezttari Crepidula. 
Lam. c 
