416 ENTOZOA. 



One of the most extraordinary genera of this family is the 



Hectocotyle, Cuv. 



Long worms, thickest and compressed at the anterior extremity, in 

 which is the mouth, whose inferior surface is completely covered 

 Avith numerous suckers arranged in pairs, to the number of sixty or 

 a hundred ; there is a sac on the posterior extremity Avith the folds of 

 the oviduct. 



H. octcpodis, Cuv., Ann. dcs Sc. Nat., XVIII, pi. xi. From 

 four to five inches long, and with a hundred and four suckers or 

 cups; it lives on the Octopus rugosus — Sepia rugosa, Bosc. — 

 and penetrates into its flesh. The iMcditerranean. 



H argonauts; Trichocephalus acetabular if;, DpIIc Chiaie 

 Mem., p. ii, pl. 16, f. 1, 2. Siualler, and with but seventy 

 suckers. It lives on the Argonaut. 



Here, perhaps, should come the genus 



ASPIDOGASTER, BcEV., 



Where the venter is furnished with a lamina, excavated by four 

 ranges of fossulae. 



A. conchicola, Bser., Ac. Nat. Cur. XIII, p. ii, pl. xxviii. It 

 is very small, and lives on Muscles. 



I cannot help thinking that we should also approximate to Fasciola 

 most of the animals contained in the genus 



Planaria, Mull*, 



Although they do not inhabit other animals, but merely live in salt or 

 fresh water. Their body is depressed, parenchymatous, and without 

 a distinct abdominal cavity. The oral orifice, placed under the mid- 

 dle of the body, or more posteriorly, and dilated into a little proboscis, 

 leads, as in Fasciola, to an intestine whose numerous ramifications 

 are formed in the thickness of the body. A vascular network occu- 

 pies the sides, and behind the alimentary orifice is a double system of 

 genital organs. They also enjoy a reciprocal coitus. Small black 

 points are observable, which probably are eyes. 



These animals are extremely voracious, and do not even spare 

 their OAvn species. They not only multiply in the ordinary manner, 

 but are reproduced with great facility by division. They even ex- 

 perience spontaneous divisions. 



* At the period of my first edition, it was by conjecture ouly that I placed the 

 genus Planaria here, having no sufficient anatomical data to give me an idea of its 

 natural affinities. Since then the observations of MM. R. Johnson, Phil. Trans., 

 Dallyell, Monog., Beer., Ac. Nat. Cur., XIII, Duges, Ann. des Sc. Nat., XV, and 

 those made by myself, appear to confirm this classiflcation, which has been adopted 

 by M. de Lamarck. 



