On the Classification of Nemertes and Planarie. 
sei whence nervous threads depart to distribute themselves 
in the body. If we further state that, as in the greater number 
of Moljuscs, the surface of the body i is covered ‘with vibratory 
ciliz which help their movements, movements generally slow, 
deprived of energy, then we directly arrive at the idea that 
Nemertes are really Molluses,—Molluses of a low rank, being * 
parallel with the worms of the division of Articulata by the 
analogy of their form 
Having discussed ede the value of the nervous system as 
the predominant character of the division, exclusively of any 
other character, it remains only for me to state that the nervous 
system of Molluscs: there exists a cephalic mass more or less 
lobed, toa either the superior esophageal ganglion of 
other Mollus r that same ganglion to which, on account of 
the peculiar ibe of the body, are added the two or three abdom- 
inal ganglia. Nervous threads are distributed in all directions; 
two of them more voluminous than the rest, but uniform in 
structure, run along the sides of the animal, and sending off 
thinner threads without showing in their course those ganglia or 
swellings which distinguish the nervous system of Articulata, 
such as it is in Malacobdella, Peripates, &c. 
The disposition of the nervous system of Nemertes, then, is 
merely analogous to that of Annelids; its structure is that of the 
nervous system of Molluscs. 
ly. 
The position of Planarie in the division of Radiata is not less 
curious than that of Nemertes. Included in the second order of 
intestinal worms, the Parenchymata, they are brought near the 
T'rematodes, to which they have only analogies, in uve same 
sense as those that Nemertes have to the Intestina cavitari 
The Intestina parenchymata have been withdrawn Aer the 
division of Radiata and brought into that of Articulata, and for 
he same reasons as that of the cavitaria. The ae eae = 
course, have thus been compelled to follow them in the sa 
manner as Nemertes have followed the latter. But also little re 
vestigated at that time, their affinities with Molluscs have escape 
the eyes of zoologists. 
The Planariz are not parasitical as ‘Trematodes are, and it 1s 
believe, is however of the highest interest. Indeed in Teno 
pits pe sre is constructed upon an analogous plan with 
Planaria ; but the digestive system, as wah 
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