for the Microscope. 75 



wedge-shaped segment proceeding from one extremity 

 towards the centre. Concentric lines very close and 

 numerous over the entire surface. 



563. TROUT SCALE (Salmo fario). Small, irregular, 

 ovate or elliptic, with coarse concentric lines nearly to the 

 centre. 



564. GREY MULLET SCALE (Mugil capito). Shortly 

 pear-shaped, depressed at the smallest, and convex at the 

 broadest end; the former with about eight longitudinal 

 ribs and numerous transverse concentric striae. The 

 broadest end apparently reticulated with the lines of short 

 obtuse spines. 



565. DOG-FISH SKIN (Acanthias vulgarisf). Whole 

 surface covered with small, short, arrow-headed spines. 

 The species is uncertain from whence this skin was 

 obtained. 



566. EEL SKIN (Angttilla acutirostris). A piece of eel 

 skin may be cleaned and mounted in balsam to show the 

 arrangement of scales. 



567. THORNBACK SKIN (Raia clavata). Covered with 

 curious horny hooks, variable in size. A portion, where 

 the hooks are small, should be selected as furnishing the 

 neatest object. 



568. FEATHER HOOKS. The barbs of the feathers of 

 a goose will afford an example of the hooks on the barbs, 

 so often alluded to by authors. 



569. FEATHER. The upper portion of a small feather, 

 such as that of a Gold Crest or, perhaps better, of a 

 Humming-Bird, affords a good example of the usual form 

 of feather structure. 



570. FEATHER OF FOWL (Gallus Bankiva, var.) The 

 shining neck-feathers of the male of some varieties of the 

 Barn-door Fowl have the horny shaft and its branches 

 expanded in a blade-like manner, which occasions the 

 glossiness. 



571. FEATHER OF PEACOCK (Paw cristatus), The 

 green-bronzed feathers of the Peacock should have a small 

 portion mounted with a disc of pink or crimson sheet- 

 gelatine as a background. 



