ON ANNELIDA. 4-5 



Fabricius, we are indebted for a considerable number of ob- 

 servations on the European species of nereis, as well as on 

 many other animals of the Linnaean class of vermes. The 

 first has proposed some changes in their distribution, intro- 

 ducing an entire order, and at the same time a tolerable num- 

 ber of genera. 



By him, however, the class vermes is still divided into but 

 five orders, as he has united the last two of Linnaeus, 1. In- 

 fusoria, for a numerous group of animals which he supposed 

 were produced in vegetable or animal infusions, and his la- 

 bours are all that we yet possess on this subject; 2. Helmin- 

 thica, or worms, in which he ranges, in two distinct divisions, 

 the intestinal worms, and the hirudo in one, and all the 

 cbetopoda, comprising among them the lumbrici, in the other; 

 3. Mollusca, the same as Linnaeus, abstracting the chetopoda, 

 but leaving the planariae, the fascioli and the medusae, with 

 the true naked mollusca; 4. Testacea ; 5. under the name of 

 Cellularia, the lithophytes and zoophytes of Linnaeus; be- 

 sides some very curious observations on the reproduction of 

 the naides, and nereides, and the distinction of a great number 

 of new species, science is indebted to this author for the esta- 

 blishment of the genera Nais and Araphitrite, and the more 

 exact circumspection of those previously established. His 

 researches were subsequently made available by Linnaeus 

 himself and several of his successors, in modifying the Sys- 

 tema Naturce. 



Though the celebrated naturalist, Blumenbach, has almost 

 exclusively followed Linnaeus, in his methodical distribution 

 of worms, he has nevertheless introduced an observation, as 

 characteristic of the class, namely, that it never possesses 

 articulated organs of motion, in opposition to what he had 

 said concerning the insects, in which those organs are articu- 

 lated ; " a character," he adds in a note, " which appears to 



