172 Zoological Collections. Vertebrafa* 



on the surface of the external membrane, the homy sheath of the back of the 

 feather, or that longitudinal band, to the two sides of which the barbs are 

 attached; and on the surface of the internal membrane are formed the 

 substance of the shaft, and the pellicle, also horny, which encloses it 

 inferiorly. The line opposite to this has no other use than to establish a 

 solution of continuity between the barbs of one side and those of the other. 

 Thus, whilst they remain in their case, the barbs curve round the gelatinous 

 medulla, and surround it on both sides. As the shaft and barbs acquire 

 consistence, they pass through the extremity of the capsule, and appear 

 externally, pushed along by the increase of the base of the gelatinous 

 medulla till the whole of the barbed portion of the feather is protruded. 

 The shaft and barbs are, as we have stated, secretions of the striated 

 membranes which envelop the gelatinous medulla ; but the medulla itself 

 furnishes the matter of this secretion. M. Fred. Cuvier thinks that the 

 spongy substance which fills the shaft is derived from it. 



As the development of the feather advances, the summit of the medulla 

 becomes empty, and forms a cone, or a kind of membranous cap, which 

 separates from the capsule, together with the portion of the shaft and barbs 

 which correspond to it. Many of these successive cones are then lost, 

 falling off as they pass out, so that there is none left on the internal surface 

 of the shaft. In certain species, or under certain circumstances, the point 

 of the medulla is double, and then the shaft takes with it one of these 

 points, whence there come to be a series of cones in the centre occupying 

 the axis, and forming cellules : but, in general, this axis is filled with a 

 spongy matter, and its inferior part alone binds in its groove a slight fold of 

 the medulla which has formed it. When all the grooves (wherein the barbs 

 and the portion of the shaft which carries them are formed,) are filled by 

 the horny matter, and the barbed part of the feather is finished, this horny 

 matter expands uniformly around the medulla, and forms the quill of the 

 feather. In progress of time, when the quill has acquired the due con- 

 sistence, the internal medulla becomes dried up, and divides into cones or 

 cups, arranged one upon the other ; but these latter cones never pass out — 

 the quill, which is now hardened, and closed by the shaft at the opposite 

 extremity to the umbilicus, will not permit their egress, — they remain in the 

 interior, and constitute what we commonly call the jAih of the feather. 



Thus we see, that the formation of a feather differs only from that of a 

 tooth in the nature of the substance which is deposited between the two 

 tunics ; but a tooth takes many years to be perfected, and there are but two 

 series produced in one part of the jaw, and only one in the other. Feathers, 

 on the other hand, are developed in the course of some days ; they attain a 

 length of from one to two feet and more in many birds, and they are almost 

 all rei>ewed every year — in many species, even twice a-year. It may be 

 conceived, then, how much energy the organization of birds must exercise, 

 and how many dangers must accompany so critical a period as that of the 

 moult. — Baron Cuvier, Rapport. — Mem. de V Institut. Tom. IX. p. cxlvi. 



Notice of the Parr ; in answer to Sir W. Jardine's Queries on the Natural 

 History of the Salmon, ^c. By William Greene, Esq. (In a letter to 

 the Editor.) 



Sir, — In a list of queries, by Sir William Jardine, published with a 

 view to collect facts, for elucidating the natural history of certain fishes, I 

 observe an inquiry, whether the Parr of Scotland be the same with the 

 Brandling of the northern counties of England. It had never before^^occurred 

 to me as a matter of doubt, that the little fish, found in such plenty in the 

 Tyne and the Derwent, differed, except in name, from that which abounds 

 still more in the Annan and the Nith. They are distinguished from the 

 common trout, by the same indistinct dusky bars on the sides ; from which 

 circumstance, the fish, I imagine, derives its English name, being striped or 

 brindled ; as the worm with a streaked tail is, in like manner, called the 



