BOOK TENTH. 



CEPHALOPHORA. 



CLASSIFICATION. 



§201. 



The 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 I'ight 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, Hetei'opoda, and Gastero- 

 poda, since it belongs equally well to Cephalopoda ; but I have adopted it 

 for the sole reason of beins; unable to find a better. ^^' 



The sub-order Apneusta with its two families Anangia and Angio- 

 phora, has been established by Kclliker 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 veigleich. Anat.) has al- He has placed these, with those which Quatre- 



naily used tliis word in tlie same way. , fages has described under the name of Fhleben- 



- Kiilliker has cumraunicated to me a yet un- terata, in the division of Apneusta which he 



puhlir-lied work in which he has described, beside divides into two sections : 1. Augiophora, having 



FtaifWnui and Po/(/cera, three new genera of the a heart and rudimentary vascular system. 2. 



inferior Gasteropoda, under the names of Acan- Anangia, without either heart or vessels. 

 thtua, l.issosoma, and Rhodope 



