SCIENTIFIC NEWS. yt 



The history of animals has witnessed the completion of Olhrier's Cola- 

 Mr. Olivier s grand work on coleopterous insects, and is en- °P tenE fim» h - 

 riched with a description of all the gelatinous animals in- 

 cluded under the name of medusa by Linnaeus. Mr. Peron, Medusa, 

 who collected a great number in his voyage to the south, 

 has increased this family to more than a hundred and fifty 

 species. The following is his account of their singularities. 

 ** Their substance seems to be merely a coagulated water, 

 yet the most important functions of life are exercised in it. 

 Their multiplication is prodigious, yet we know nothing of 

 the peculiar mode in which it is effected. They are capable 

 of attaining several feet in diameter, and fifty or sixty 

 pounds in weight, yet their nutritive system escapes our 

 eyes. They execute the most rapid and long continued 

 movements, yet the details of their muscular system are 

 imperceptible. They have a very active species of respira- 

 tion, the true seat of which is a mystery. They appear 

 extremely feeble, yet fish of considerable size form their 

 daily prey, and dissolve in a few moments in their sto- 

 mach. Many species of them shine amid the darkness of 

 night like balls of fire; and some sting or benumb the hand 

 that touches them : yet the principles and agents of both 

 these properties remain to be discovered." 



All the medusas have a gelatinous body, nearly resem- 

 bling the cap of a mushroom, which Mr. P., after the ex- 

 ample of Spallanzani, names umbrella', but they differ in Specific cha- 

 wanting or having a mouth ; in the mouth being simple or racters « 

 multiplicious ; in the presence or absence of a production 

 resembling a pedicle; and in the edges of this pedicle, or of 

 the mouth itself, being furnished with tentacula, or fila- 

 ments more or less numerous. From these characters Mr. 

 P. forms divisions and subdivisions, under which every pos- 

 sible kind of medusa may be arranged. Very fine paint- 

 ings by Mr. Lesueur, who accompanied him on the voyage, 

 illustrate the various forms and colours of these auimals, 

 many of which are very pleasing to the eye. 



To this examination of their external characters, Mr. P. Their interior 

 has added very interesting remarks on the interior structure structure « 

 pf these animals ; and in particular of that genus, which 

 Mr. Cuvier named rhizoslome, because he supposed, that 



the 



