BOOK TENTH. 
CEPHALOPHORA. 
CLASSIFICATION. 
§ 201. 
Tue organization of the animals composing this class is quite dissimilar ; 
and, as in the preceding class there were species which approached the 
Zoophytes, so here there are those which are scarcely above the Worms, 
Thus, it is a question whether the genus Sagitta, which is placed at the 
head of this class, is really in its right place, although all the attempts to 
place it in another group have furnished results no more satisfactory. 
Then again, it may be objected that the name Cephalophora should have 
been given to a class composed of the Pteropoda, Heteropoda, and Gastero- 
poda, since it belongs equally well to Cephalopoda ; but I have adopted it 
for the sole reason of being unable to find a better.” 
The sub-order Apneusta with its two families Anangia and Angio- 
phora, has been established by Kcdliker in opposition to the other Gastero- 
poda, which have distinct respiratory organs.” This division, composed 
of small and very interesting species, is the more admissible since it is 
‘based upon the anatomical structure of these animals; and also as the 
most recent investigations have shown that the term Phlebenterata used by 
Quatrefages, is improper. 
ORDER I. PTEROPODA. 
Animals with natatory organs composed of wing-like or fin-like cutane 
ous lobes, symmetrically arranged upon the two sides of the body. 
1 Meckel (Syst. der vergleich. Anat.) has al- He has placed these, with those which Quatre 
ready used this word in the same way. JFages has described under the name of Phleben- 
2 AKolliker has communicated to mea yet un- terata, in the division of Apneusta which he 
published work in which he has described, beside divides into two sections: 1. Angiophora, having 
Flavellina and Polycera, three new genera of the a heart and rudimentary vascular system. 
inferior Gasteropoda, under the names of Acan- Anangia, without either heart or vessels. 
thina, Lissosoma, and Rhodope 
