OF CONCHOLOGY. 



105 



snail, living, from a correspondent in California. During the 

 rainy season on the West Coast my shells Avere exceedingly 

 active, and decidedly nocturnal in their habits. They laid eggs 

 respectively on January 19th, Feb. 9th and 19th, this year, 

 burying themselves in the earth all except the upper part of the 

 shell during this operation, and remaining so for about 48 hours; 

 each laying from 100 to 150 eggs in a mass. The eggs are 

 about one millimetre in diameter ; I kept each lot separate, and 

 found them to hatch in from 22 to 23 days. The young animal 

 is more of a bluish cast than the old ones, and the shells when a 

 day old have already attained the size of 4J millimetres and are 

 yellow banded. 



I am sorry to record the loss of many of my young specimens 

 from a dreadful piece of cannabalism. I kept in the same box 

 with them a Helix hortensis, which, on the approach of cold 

 weather last autumn, became torpid and buried itself in the 

 earth : yesterday at noon it revived, and by this morning had 

 eaten up at least 75 or 80 of the young Helix fidelis ! — New 

 Bedford, Mass., April 8th, 1866. 



We may notice that a splendid specimen of Helix Mormonum, 

 recently sent to us alive, by our friend Dr. Wesley Newcomb, of 

 Oakland, California, is also almost entirely nocturnal in its 

 habits. This individual frequently exhibits its buccal plate 

 very prominently ; the jaw is of large size and deep yellow in 

 color. 



Polymorphism among Bryozoa. — Dr. A. F. Smith, in his in- 

 augural dissertation, published at Upsala in 1863, has shown 

 conclusively the existence of Polymorphism among Bryozoa. 

 His investigations are based upon the marine species of the Scan- 

 dinavian Coast. He shows that there are no less than six differ- 

 ent forms of shells, which are probably never all found on the 

 same stock. According to his view the Avicularia are only modi- 

 fied cells. Stoliczka was the first to call attention to the Poly- 

 morphism of Bryozoa in his studies of fossil Bryozoa. The paper 

 by Smith is unfortunately not illustrated, and is written in a 

 language avaihible to but few naturalists. — Alex. Agassiz, in 

 Am. Jour, of /Science and Arts, July, 1866. 



The name of Helix Bridgesii, which I gave to a species col- 

 lected by the late Mr. Bridges in Nicaragua, being preoccupied 



