The Lake ayid Brook Lampreys of New York 455 



common bronchus by a small opening about the size of the 

 external opening. The velum gradually atrophies and soon 

 almost disappears. It is stated by Bujor that in the metamor- 

 phosis, the tissues return to an embryonic condition and then 

 are reformed into the tissues of the adult. "]>s difFer- 

 ents tissus des organes larvaires se regenerent completement 

 pendant la metamorphose," (Bujor, '91, pp. 77, 88). Es- 

 pecial care was taken in investigating the transformation to 

 determine something of the activity of the animals and their 

 mode of life. The first transforming ones were obtained the 

 last of August. The last just transformed ones from the na- 

 tive habitat were obtained the middle of October. Aquaria 

 were prepared with sand and gravel, thus imitating as closely as 

 possible the natural conditions. Into these aquaria the trans- 

 forming animals were placed as they were received and each 

 aquarium carefully labeled with the date and the stage of de- 

 velopment. All of the animals that were in good condition very 

 soon disappeared in the sand. Those with a fully developed 

 sucking mouth surrounded by the oral fringe of papillae (PI. 

 VII, fig. 19-21), also buried themselves. Some of these were 

 so far advanced that the horny tips to the teeth were already 

 visible with a lens. It is therefore believed that the animals, 

 in nature, remain under the protection of their early home 

 until they are fully armed and ready to get their food in the 

 usual adult fashion. 



The activity of the animals seemed not at all lessened. In 

 a vessel of water they swam with the same vigor as untrans- 

 forming larvae and frequently like them made vertical leaps of 

 10 to 20 centimeters to escape from the dish. The respiration 

 seemed in no way interfered with. So far as certain struct- 

 ures are concerned, at least, there seemed no tendency to re- 

 turn to an embryonic condition. The ova, for example, in 100 

 millimeter larvae have the unmistakable characters of the ova 

 in young adults. None of these characters are lo.st dur- 

 ing transformation. Certain profound changes take place, 

 that is certain, but these changes appear to the writer rather 

 the additions to or rearrangement of tissues common alike to 

 the larva and the adult, new structures also appear and purely 



