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The President called the attention of the Society to a 

 stuffed skinof an American Manati, and the mounted skele- 

 ton of the same animal, which were before them. He 

 stated that there had been long established two species of 

 this animal, one dwelling in the waters of tropical Africa, 

 and the other of America, — Manaius Senegalensis and 

 Americanus. They belong to the class of herbivorous Ce- 

 tacea. He proceeded to point out the details of the skele- 

 ton, and of its external configuration. The skeleton was 

 nearly complete, lacking only some of the bones of the 

 anterior extremity. He concluded his remarks by present- 

 ing the specimens to the Society. 



Prof. Agassiz said he could not let the occasion pass 

 without calling the attention of the Society to the great 

 value of the specimens just presented by the President. 

 He stated that the skin was the only one of this animal in 

 any scientific collection. Of the bones, there is one per- 

 fect skull, and part of another in the Collection of the 

 Academy of Natural Sciences in Philadelphia ; a broken 

 cranium and a few vertebrae and ribs in the Collection of 

 the Medical College in Charleston, S. C. The skeleton 

 was therefore of extreme value. 



Prof. Agassiz said that he had, during the past season, 

 been studying the metamorphoses of the Lepidoptera, and 

 had particularly noticed a stage in the transformation of 

 these insects not usually described. Burmeister, however 

 had observed it, but had not made use of the hint which it 

 gave for a natural classification of insects. 



The Lepidoptera are known in three conditions, that of the 

 worm, jointed, and furnished with jaws, the chrysalis, and the 

 perfect insect with four wings. The condition which was first 

 noticed by Burmeister is concealed somewhat under the skin 

 of the caterpillar. At a certain period it swells in the tho- 

 racic region, becoming extremely sensitive to the touch from 

 an inflammation of the skin in this part. On making an inci- 

 sion at this place, the rudiments of four wings appear before 



