HARD WICKE 'S S CIENCE- G OS SI P. 



Ill 



colour above, and silvery white below ; but they 

 have a chameleon-like facility in adapting the colour 

 of their coats to that of surrounding objects. They 

 are of a Avell-rounded and beautifid shape, especially 

 towards the tail, wdiich is admirably cut, and in its 

 motions gracefulness itself. Every amateur aquarium- 

 keeper is familiar with the aspect of these creatures — 

 their big eyes, chubby lips, and supple tail, and 

 their extraordinary pugnacity and destructiveness. 

 -Most seaside little boys are aware of the extensive pre- 

 dominance of a certain species thereof, in rockpools 

 or tiny inlets of the coast ; and most microscopists 

 are experienced in their illustrative excellencies in 

 the way of exhibiting the general or the particular 

 characteristics of piscine blood circulation. These 

 sticklebacks gormandise voraciously on worms, the 

 fry and roe of other fishes, but they worry and 

 devour other small fish that come in their way, 

 nibbling heartily at their tail and fins, even at those 

 of their own species. The skin is without scales, 

 but lavishly furnished with areolie filled with a 

 coloured oil ; whereby the colour of the surface 

 may be varied at will, or rather, according to the 

 involuntary excitement of certain dermal nerves. The 

 sides of the body are, however, encased in a more 

 or less complete armature of bony plates ; the head 

 and face are also enclosed in a bony buckler of plates 

 stoutly soldered together, and the bone beneath the 

 eye is especially developed. The first dorsal fin 

 is represented by a number (three to fifteen) of 

 detached spines ; and a single stout spine represents 

 the ventral fin. The habits of these most vivacious 

 creatures are extremely interesting. The marine 

 species exhibits a "beautiful " illustration of Darwin's 

 views concerning the "Struggle for Life," the 

 " Survival of the Fittest," &c. About April or May, 

 some mature male stickleback aspires to procreate a 

 family of little sticklebacks, selects some special 

 position — some "coigne of vantage" among the rocks. 

 There among the screening fronds of fucus and coral- 

 line seaweed, he proceeds with tremendous energy 

 and signal architectural skill to construct a nest 

 as follows : Some of the pendent tufts of seaweed in 

 his vicinity are, by means of his snout, neatly arranged 

 and bound round and throughout by a very long 

 silk-like thread lavishly ejected from his body, until 

 a pear-shaped mass (like a small jam-roll) is formed 

 about eight inches long. The top is then constructed, 

 and a small hole is left therein, or at one side, in 

 order to permit access within. The male now in 

 full dress goes a-courting, and presently some coy 

 and confiding female stickleback, after a vivacious 

 demonstration of caressing and solicitation, is induced 

 to enter into the snug weed-woven nest. In a few 

 minutes the spawn is laid, and the female imme- 

 diately decamps by a side-door pierced by her own 

 snout. And now comes the tug of war. The male 

 stickleback after impregnating the spawn, forthwith 

 «' mounts guard" over the nest. In the performance 



of his nursery duties he exhibits a lavish prodigality 

 of life-energy. With invincible assiduity he watches- 

 the cradle, removing all obstruction, ever on the 

 alert, prying into the hole to see if all's right inside, 

 looking about with his snout, repairing and trimming; 

 up the. precious structure, occasionally fanning it 

 with the pectoral fins so as to aerate the contents 

 thereof, and lastly, stoutly repelling every attack of 

 the enemy. It is in sooth a case of "the struggle 

 for life ; " for frequently, with virulent animus and 

 true pugnacious energy, will a colony of breeding 

 sticklebacks attack one another. Very beautiful 

 they are at this time, and they ought to show better 

 manners. But the eggs are exceedingly tasty and 

 luscious, so that a perpetual struggle (see Darwin) 

 is carried on to make a dinner of each other's spawn 

 or fry. The "mills" are frequent and ferocious, 

 the sparring being conducted with much "science" 

 and vigour (colours glow, teeth and spines ply 

 energetically), until eventually either party "comes, 

 up smiling," or "throws up the sponge." In about 

 three weeks the fry are hatched, and then the vigil- 

 ance of the parent become doubly redoubled. He 

 spars and brawls with his neighbours more obstrep- 

 erously than before, he checks the premature wander- 

 ings of the fishlings, bringing back the truants to the 

 nursery in his mouth, and conducts himself generally 

 as a veritably full-commissioned, though excessively 

 fussy, and officious parent or guardian. From June 

 till the winter the fry in various stages of size and 

 development may be observed in rock-pools or under 

 stones between tide-marks. 



{ To be contiinied.) 



MICROSCOPY. 



New Zoophyte Trough. — When in London at 

 Christmas to obtain a special form of microscope, I 

 saw, amongst other apparatus, at Watson's, 4 Pall 

 Mall, a form of zoophyte trough that was quite new 

 to me. I have used it since then, and I find that it 

 works admirably, and is suitable for everything 

 except the largest objects. Its advantages are that 

 it is very light, is pleasant to work with, does not 

 slip readily from the fingers, and can bear a fall 

 without breaking. The only breakable parts are 

 two slips of glass, and they can be replaced for 

 almost nothing. It can be cleaned with the greatest 

 ease. It is very cheap at 3^-. 6d. when compared 

 with the zoophyte troughs which cost in many cases 

 about double ; above all, when it is considered that 

 with almost no trouble it can be ;nade to do the 

 work of an entire set of the medium and small sizes. 

 It consists of two thin slips of plate glass, ground 

 edges, 2 in. by I in., which form the back and front 

 of the trough ; the bottom and sides are formed ot 

 half of an indiarubber rin-, N\hich is placed between 



