1867.] 125 [Lyman. 



oring matter, rather dark yellowish-brown. The cells are about .001 

 inch in diameter, of irregular shape from mutual pressure, and much 

 resemble the larger cells of the yeast fungus, as figured by Jabez 

 Hogg, in the Proceedings of the Microscopical Society of London, 

 January, 1866. 



The interior substance is very -dense and opaque; only very small 

 fragments could be obtained transparent enough for observation. The 

 only structural feature that could be made out was a linear arrange- 

 ment of the material. When these small fragments were crushed on the 

 glass, a few filaments of mycelium, and a few very small cells, some of 

 them in moniliform chains of three to eight cells, were found. Also occa- 

 sionally, groups of yet more minute cells, .0001 inch, probably spores, 

 but nothing could be determined as to the position of mycelium, cells 

 or spores, in the perfect plant. 



It is highly probable that the long immersion of the fungus in al- 

 cohol has produced some change in its texture and density, such as to 

 prevent the separation and distinction of the various parts of the or- 

 ganism, and that a satisfactory analysis can be made of it only on 

 fresh specimens. It may be also that the most of the internal sub- 

 stance when dried naturally, would prove to be spores, like " puff 

 balls," and other similar fungi. 



Mr. Theodore Lyman exhibited models of fish ways which 

 had recently been constructed on the Merrimack, under the 

 direction of the State Commissioners appointed to investi- 

 gate obstructions to the passage of fish in the larger rivers. 

 He prefaced his remarks upon them by an account of the 

 habits of the migratory fishes. 



The shad (Alosa prcestabilis) is one of the large species of herring 

 that go each year, from the sea to fresh water, to dejjosit their spawn. 

 The alewlfe (Alosa tyrannus) is a smaller species, having the same 

 habit. The shad is notable, not only for its natural abundance, but 

 for the wide ocean province which it inhabits ; for, while Cape Cod 

 makes, for many fishes, the boundary between the inhabitants of the 

 northern and the southern waters, the shad seems equally to flourish 

 in the latitude of Savannah and of the Gulf of St. Lawrence. With 

 the first indications of spring weather, these fish, driven by the resist- 

 less instinct of propagation, approach in vast shoals the mouths of the 

 great rivers. They begin to run up the Savannah as early as Christ- 

 mas ; the Chowan, Roanoke, and Potomac, in February ; the Dela- 

 ware In the middle of March; the Hudson, in early April; the Merri- 

 mack, late in April ; and the Bay of Fundy in the middle of May. 

 It is the theory of Professor Agassiz that they do not in one great 



