Cr 
PLATE XY. 
. 
. The 47gonauta argo sailing. 
. Ocythoé Cranchii, Leach, sitting within the shell. 
. Clio Borealis. 
a. The body. 
b. _.. viscera seen through the common coverings. 
cc. .. tubercles of the head, and the holes into which the three tenta- 
cula on each side retire. 
dd. .. branchiz and fins. 
, Pneumodermon, front view. 
a. The body. ' | e. The chin or pointed fleshy appen- 
Bite 3.7, eae. dage. 
c. mouth. ifs oe INS. 
ad! ps: g. .. branchie. 
h. .. trunk of the branchial vein. 
, Pneumodermon, with ¢he skin divided to shew the position of the peri- 
cardium and fleshy tunic. 
i... The auricle. 
k. .. pericardium. _ 
ll. .. fleshy tunic with its longitudinal fibres. 
. The Eolis, placed obliquely, shewing the belly and right side. 
. Scyllea pelagica, on the right side. 
HH. The under surface of the foot hollowed into a deep furrow, by 
which it suspends itself. 
G. .._ mouth. 
AA. .. two tentacula. 
BC. Two pair of membranous flexible ‘These and the back bear the 
Wings. branchiz in the form of little fi- 
D. A crest on the tail. brous tufts. 
E. The orifice of generation. 
F. .. orifice of the anus. 
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