259 
Milne Edwards, Owen, Prosch, Rang, Rathke, Risso, Steen- 
strup, Trincliese, Valenciennes, Verany, and Yrolik, some 
still living and working at the Ceplialopoda, others speaking 
to us through their already accomplished work, have thrown 
a flood of light on the subject, and prove that the interest in 
this class of invertebrates has been handed down from one 
generation to another, and still survives ; nor must we forget 
that the recently returned, and now celebrated "Challenger 
Expedition " has furnished material which promises to add to 
our knowledge of the Cephalopoda, for the numerous marine 
treasures brought to England include at least one perfect 
specimen of the Pearly Nautilus, which was captured between 
New Zealand and the Fijis, in a depth of 300 fathoms,* and 
it is very gratifying to learn that this and the other Cepha- 
lopods collected have been placed in the hands of a distin- 
guished English professor for examination and description. 
STSUCTURE. 
The name Cephalopoda (Greek, KecpaXrj, head ; ttov?, foot) 
has reference to the peculiar arrangement of the lobes 
(brachia) of the foot, in a circle around the head of the animal ; 
this feature alone serves to distinguish the members of the 
group from all other molluscs whatsoever ; whilst their highly 
developed nervous system and complex sensory organs at 
once declare their great superiority physiologically, and place 
them at the head of their sub-kingdom. 
General Form and Relations of the External Parts. 
Figs. 1 and 2 arc sketches of a Cephalopod,t showing the 
relation of the arms to the head just mentioned, a relation 
which is constant in all the genera ; and also illustrating the 
following common characteristics : — 
• " Log Letters of the Challongcr, by Lord Georgo CtimpbcU," London, 1877. 
f From a Rpccimcn of Onimatostreplios todurus, DlUo Chiaje, preserved in 
spirits, and collected in the Iri.sh Sea, lb76. 
