628 SCIENTIFIC RECORD FOR 1884. 



Serrated Throat Appendages of Amia. — The so-called "mud-fish" or 

 "lawyer" [Amia calva) of our Western and Southern lakes and rivers, Is 

 especially interesting to the morphologist on account of the peculiarities 

 of structure and the habits coincident therewith which it exhibits, and 

 also, more especially, from the fact of its being- intermediate between 

 the old-fashioned and the new-fashioned fishes. One of the peculiari- 

 ties of this fish is the existence of " serrated appendages" or " flagella" 

 beneath the throat, which are attached by their bases to the lateral as- 

 pect of the sternohyoid muscles. Experiments have been made, under 

 the direction of Prof. R. Ramsey Wright, of University College, Toronto, 

 to elucidate the physiology of these appendages. His specimens of 

 Amia, " after being in captivity for some time, became very sluggish, 

 and hardly any movements of respiration could be detected. After the 

 fish had been removed for a little out of the water, however, and then 

 returned to it, the movements were sufiiciently active to disclose the fol- 

 lowing facts : 



" During the enlargement and filling of the cavity of the mouth, the 

 posterior flexible (and muscular) border of the gill-opening is tightly 

 applied to the soft parts behind the gill-opening. When the mouth-cav- 

 ity is quite full, the mouth closes, the muscular border of the gill-cover 

 releases its sucker-like hold of the soft parts, and the water is driven 

 out by the contraction of the walls of the mouth-cavity." {Science, v. 

 4, p. 511.) 



Development of the common American Catfish. — Mr. John A. Ryder 

 has published the results of an investigation into the embryology of 

 a common American catfish, the Amiurus alMdus. The eggs of this 

 species are laid in a large depressed mass, and are adherent together 

 and to the object upon which they are laid. They are about one-eighth 

 inch in diameter and hatch in about six days, when the water is of the 

 temperature usually prevalent duriug the breeding season of the species, 

 which, about Washington, is in July. The male, after the eggs are laid, 

 faithfully guards the eggs, hovering over them, and fanning the mass 

 of ova with his lower fins, apparently for the purpose of forcing water 

 through them. 



Each egg is covered by two envelopes, an inner true zona radiata 

 and an outer elastic adhesive lamina, which is raised up from the inner 

 one upon a series of columns consisting of the elastic substance. It 

 thus results that a space is formed between the inner and outer envel- 

 opes of the egg, which is filled with water. The outer elastic envelope 

 permits the male to make comparatively violent movements while re- 

 newing the water over the ova without detaching them from one 

 another or from the objects to which they are afBxed. Indeed, the elas- 

 ticity of this outer membrane is surprisingly extensive in the living ova. 



On the second day the barbels appear in blunt processes, thus early 

 defining the order to which the embryos appertain, They arise at th^ 



