32 E. 8. Morse—Cilassification of Mollusca 
(8.) Principal nerve masses, consisting of ganglia, which are ad- 
jacent to, or surround the agus 
(4.) Intestine bending patie or having an aroma flexure. 
(5.) Heart on the outer bend of intestine. 
[ Sac open at { CEPHALOPODA, 
a OR | autetice end. ({ GasTEROPoDA. 
Aout ae fees { LAMELLIBRANCHIATA, 
Sacoata. + 
peperens oR f Sac open at 
HEMITY posterior end. igh ceanierntt 
Mouth 
: Ladasiterty. Ls ac Cloned. 1Pe Bracuroropa, 
OLY 
must now consider the relations of ei Saecata to the 
dian” branches of the Animal Kingdom. In the paper of Pro- 
gamma’ ‘pie, ve degradational ; the ‘Radiates are regarded 
as dapradateonal; "ait evel eek hemiphytoid. He employs 
also, the terms use above, namely, ons for true animal 
org vata Phytozoic, for plant-lilee form 
lying these terms to the classes or oe of nate, we 
ire the following : 
te are! CrPHALOPO 
Hotozotc. A GaAsTEROP nn 
Gammatypic, LaMELLIBRANCHIATA. 
a . § Tuntoara. 
Peencsnee ( Bracuiopopa. 
Puyrozoic. ae Potyzoa. 
ellibranchiates may be considered the essential embodiment of 
the branch to which ats belong. Tunicates and Polyzoa may 
be compared to Radia 
Or, in considering hee freedom or fixedness in life, we have 
Cephalo pods free, as in all Verte brates ; opods, a a few 
fixed, as in Articulates ; Lamellibranchiates, many fixed, as in 
ta, with ener to the other Branches. ‘unicates, the 
greater portion fixed, though they do not compare so well with 
