41 



This charm can never belong to merely descriptive ornithology, 

 because even the best descriptions are only like mosaic stones, which, 

 when placed without rules, or arranged according to false principles, 

 give us only a scattered mass of heterogeneous materials, or a picture 

 destitute of truth. 



These claims I have urged over and over again in my dissertations, 

 but hitherto without effect. "VMien shall the time arrive when a 

 catholic spirit shall guide the destinies of science, and lead onward to 

 that triumph of true knowledge, in which every director of a mu- 

 seum, and every student of the works of nature, may take his part ? 



At present it is impossible that a naturalist can without help 

 arrange the whole materials of one class in his museum. Our mu- 

 seums are little more than great exhibitions for the people, who look 

 too often only to colour, instead of being stores of nature's trea- 

 sures, ready to be communicated to every naturalist who has proved 

 himself worthy of the name. Every museum ought to accord freely 

 and liberally the wished-for materials, for this is the cheapest way in 

 which a family can be properly named and accurately classed. The 

 common excuse that the lent materials might come to harm, is little 

 more than an excuse. Time and destructive insects will do the harm, 

 without the slightest advantage to science. 



Nisus (seu Accipiter) chionogaster, Kaup. 



Diagnosis. — Above dark blue grey, beneath pure white. 

 Description. — The male is less than the Nis. fringillarius. Above 

 dark blue grey, the crown, lorum, and a stripe over the eye- and ear- 

 cover feathers more approaching to black ; ear-covering, cheek and 

 crop with fine black quill lines ; tail with three black bauds and a 

 broader band at the end, which is white bordered ; the underside of 

 the tail has the bands more silver-grey ; the first tail-feather with five 

 bands before the large end-band ; the wings on the inner side with 

 four bands before the large end-band. Before the emarginations the 

 bands are grey, and after them whiter. 



The larger female vAi\\ a white eye-stripe, and broader black quill 

 stripe on the crop ; the cover feathers of the tibia with a fine rufous tint. 

 According to the ticket of M. de Lattre, the iris of the female is 

 orange, and that of the male dark brown, like burnt sienna. 



These two specimens were procured by M. de Lattre in Cohan, in 

 the year lvS43. 



Dimensions in millimetres. — $ § 



Head 40 45 



Gape 16 19 



Wings 173 206 



Tail 140 160 



Tibia 47 56 



Middle toe without nail ... 32 37 



We possess several species in the genus Nisus, Cuv., seu Accipiter 

 of the English authors. Most of these are very near to the common 

 Sparrow-Hawk ; and I think some of them, like the North American 



