62 
room x. abundance as to impede their motion through the 
Nat. Hist, water. Shells of the class cephalopoda, amongst 
Zoology, yyhjch arGj three species of argonauta or paper- 
nautilus; these shells are remarkable for the 
slightness of their fabric and the elegance of 
their form. They are said to be inhabited by an 
animal not unlike the cuttle-fish, which by ex¬ 
tending a pair of membranes has the power of 
sailing on the surface of the sea. A model of 
that rare and much esteemed shell the carinaria 
vitrea, or glassy paper-nautilus. Two species of 
nautilus, commonly distinguished by the appel¬ 
lation of chambered nautilus: spirula, or pearly- 
nautilus: &c. 
No. 22. Shells of .the class gasteropoda, or 
univalve shells. These are arranged from the 
structure of their inhabitants : the most remark - 
able are the elongated scutus, the animal of which 
is preserved in. No. 29, Jamaica fissurella, star 
limpet, black limpet, tortoise-shell limpet, dis¬ 
torted calyptraea, waved mitella, Chinese ditto, 
chiton squamosus, two species of a newly dis¬ 
covered genus named cryptoconchus, (the ani¬ 
mals of which are preserved in case 29,) Cra- 
cherodian earshell, staircase padoilus, wood- 
veined scaphander, with its testaceous stomach, 
(which has been described as a multivalve shell), 
lineated bulla, nut bulla, various species of 
natiea. 
