HARDWICKE'S SCIENCE-GOSSIP. 



2aj 



The Silver-fin {Leiiclscus anolostanus. No. 72 in 

 Gunther's Catalogue, vol. vii. p. 256) is so called 

 from the satin-white pigment which fills all the 

 inferior fins and the tail. This pecnliar colouring is 

 not, however, as stated by several writers, peculiar 

 to the spring and summer months. After a very 

 careful examination of thecolouring of all our fresh- 

 water fishes, we have found that the difference 

 between spring— or the breeding season — and other 

 times of the year is not so great as frequently repre- 

 sented. The Silver-fin has this satin-white glisten- 

 ing of the lower fins somewhat brighter in summer 

 than in winter; and so, too, with the gorgeous lled- 

 fin {Hypsilepis coriiutus) and the Chub {Semotilus 

 rhotheus) ; but the bright colours are not lost in 

 autumn and throughout thewinter, — theyaresimply 



writes : — " During the seventh month of the present 

 year (1S6G), I watched a company of them (Silver- 

 fins) with a greater number of the Hyhopsis procne 

 clearing out with pectoral fins and muzzle a sandy 

 basin between two roots of a stump standing in the 

 Conestoga Creek. They were excessively active, 

 suddenly turning from their employment and sailing 

 off in streaming columns, when the silver-white of 

 the fins had a pleasing and peculiar effect in the 

 evening light. As we approached, a Tropidonotus 

 sissedon swam off with a luckless Hybopsis across 

 his mouth, but soon returned to watch alternately 

 ourselves and the busy throng. Approaching 

 cautiously, he struck right and left below the 

 surface, as the minnows passed him, but often fell 

 short, till a hungry Aromochelys odorattts, having 



Fig. 139. Silver-Fin. 



duller. The peculiar colour of the fins of the Silver- 

 fin is not confined to the male fish, although in the 

 allied Hypsilepis cornutus the female fish is much 

 more plainly coloured. 



This little cyprinoid is not at all confined to the 

 smaller streams, such as where we liave described him, 

 but far out in the river, wliere the water is deepest 

 and the current strong, there, too, in little companies 

 they are often found, apparently well contented 

 with their whereabouts, notwithstanding the vo- 

 racious Rock-fish {Roccics lineatus) so frequently 

 dashes in among them, to tlie certain destruction 

 of some one of their number. 



To juvenile anglers they afford excellent practice 

 and good sport, if the mei-e pleasure of capturing 

 them only is desired, as with a small hook baitedwith 

 dough they may be taken as soon as the young 

 fisherman becomes quick enough in his movements '■> 

 for the little Silver-fins seize the hook and dart 

 away as swiftly as the wary trout rises to the fly. 



In one of the anatomical papers of Prof. Cope, 

 on our Cyprinoids, we find a pleasing note on their 

 habits,— a brightly blooming flower, as it were, in a 

 dreary desert of dry bones; and with it, we will 

 close our notice of the pretty Silver-fin. Prof. Cope 



the haste and movements of a half-fed hog, came 

 nosing his way into the midst of the unsuspecting 

 party. They, of course, scattered in all directions, 

 while he hastily explored the ground, and finding 

 no eggs, scuttled off with the Wampum snake. The 

 latter returned, and was successfully pursuing his 

 fishing when we left." 



A NEW ERECTING-GLASS FOR THE 

 MICROSCOPE. 



"jl^/rlCROSCOPISTS, when they first begin to 

 ■^^ work, or even to use, the compound micro- 

 scope, experience many difficulties and not a few 

 disappointments, produced by the inverted image 

 of the object ; the apparent top being really the 

 bottom, the right-band side really the left, and 

 vice versa, causing so much perplexity as often to 

 almost make the manipulator throw up his work in 

 disgust. In time, with practice and patience, the 

 hand becomes schooled to its work, and acts 

 almost meciianically of itself, without appearing to 

 be under the influence of the brain ; or at least the 

 hand appears to act without the brain attempting 



