QQ KANSAS ACADEMY OF SCIENCE. 



mandible fits very closely with the lower oue, something after the fashion 

 of scissors, and they are therefore well adapted to their work of feather- 

 trimming. 



On closer inspection of the shaft, we find that traces of a web still remain, 

 showing that^it did not come so by a natural growth ; so that after a careful 

 examination of the structure of the bill, and considering the uuevenness of 

 the missing webs as well as the time of its disappearance, we must conclude 

 that what nature does not do by narrowing the feather, the bird by its nat- 

 ural instinct of beauty and symmetry does with its bill. 



A CONTRIBUTION TO THE HISTORY OF THE FRESH- 

 WATER COPEPODA. 



BY F. W. CRAGIN, Sc. B., WASHBURN COLLEGE, TOPEKA. 



The study of the fresh-water Copepods, or oar-footed Crustacea, of North 

 America, has, until recently, been quite neglected. Within a few years the 

 diligence of two or three naturalists, mainly of Professor Forbes, of the 

 Illinois State Laboratory of Natural History, has given us substantial con- 

 tributions to the knowledge of this interesting part of our fauna. 



As early as 1818, Say described an American species of Cyclops; but his 

 description, like those of Haldeman, Dana, and several later authors, is im- 

 perfect and not of specific value. 



The free-swimming Copepoda known to inhabit inland waters are as fol- 

 lows: Gentropages, Osphranticum, Diaptomus, Heterocope, Epischura, Lim- 

 nocalanus, Temora^ Cyclops, Tachidius, Canthocamptus, and Attheyella. Of 

 these eleven genera, four — Diaptomus, Limnocalanus, Cyclops, and Cantho- 

 camptus — have been recorded as common to the fresh waters of the Old 

 World and the New. I add Heterocope on the authority of my friend, Mr. 

 William Patten, who informs me that a species is common in Watertown, 

 Massachusetts. 



Tachidius, in the^Old World is known only in waters made salt or brackish 

 by the ocean; but a species has been found by ]\Ir. V. T. Chambers at Big 

 Bone Springs, Kentucky, in moss wet with the mineral water. 



Temora, in the Old World has been found in both salt water and fresh ; 

 but in America has not yet been discovered in fresh water. 



Osphranticum and Ejnschura are known only in North America, having 

 been described recently from Lake Michigan and Normal, 111., by Professor 

 Forbes. 



Attheyella is as yet known only in Great Britain, one of its species living 

 in the damp roof of a coal mine. 



