August 1, 186G.J 



SCIENCE-GOSSIP. 



171 



from each corner of the mouth ; and the fourth pair 

 originate a short distance behind the third. 



The ladies Aspredo are alone concerned in nursing 

 their progeny, aud on females only are the curious 

 "fish-cradles" found, so specially contrived for the 

 conveyance of the eggs. Dr. Gunther (to whom 

 belongs the honour of first clearly pointing out the 

 use of this obscure structure) says,* "The ovaria 

 of the fish examined are two nearly empty sacs, with 

 thick walls, as if the ova had just been excluded ; 

 some of them which had not been developed still 

 remained between the folds of the interior. The 

 whole lower surface of the belly, thorax, throat, 

 and even a portion of the pectoral fins, showed 

 numerous shallow round impressions, to which a 

 part of the ova still adhered." Perhaps the reader 

 has borne in mind what I said in a previous number 

 in reference to the strange similitude there is betwixt 

 the cellular-like cavities found on the back of the 

 Surinam toad when compared to those on the under 

 surface of the female Aspredo. Towards the time 

 of spawning, the skin covering the lower parts of 

 the female Aspredo becomes thickened, and assumes 

 a spongy character. The spawn or ova are in all 

 probability deposited, in the manner usual with most 

 fishes, on a mud bank or in some other suitable 

 locality. Then the mamma presses herself on the 

 extended mass of roe, and in that way squeezes the 

 eggs into the soft sponge-like skin of the abdomen ; 

 the throat and fins are also made available for the 

 conveyance of the eggs. The spongy substance 

 between the eggs is subsequently gradually absorbed 

 by the pressure of the latter, excepting in the inter- 

 spaces, where it remains in the form of the ap- 

 pendages previously described. What becomes of 

 the infant fishes when they escape from this novel 

 hatching-machine is not known. The only described 

 species— as far as I am aware— of this genus have 

 all been brought from the river Gambia. 



Many other species of Siluroid fishes take care of 

 their progeny in different ways. The male {Arius 

 fissus), it seems, carries a small cargo of eggs in its 

 mouth. Dr. Gunther describes his finding two 

 males whose stomachs were empty (hence it is 

 fair to assume they were not in the act of devouring 

 a breakfast of new-laid eggs) . In the mouth of each 

 fish, however, were about twenty eggs, "larger than 

 a pea, perfectly uninjured, and in a forward state of 

 development." 



Europe possesses but one species of the Siluridee, 

 i\& Silurus giants,—" giants, a crafty fish, which bites 

 away the bait without meddling with the hook," 

 writes Pliny. Sly soever as it may be, nevertheless 

 it shows some remarkable traits of parental instincts ; 

 papa and mamma sly Silurus both taking an active 

 part in protecting their numerous children after 

 they emerge from the eggs. The Sudas gigus, a 



* Brit. Mus. Cat.— Fishes, vol. v. p. 173. 



Siluroid found in the large rivers Amazon and 

 Negro, and that, according to Schomburgk, attains 

 to a weight of two hundred pounds, regularly bolts 

 its entire family if apprehensive of danger. The 

 roe is never deposited, but the young escape from 

 the eggs whilst contained in the ovarium, and make 

 their way into the cavity of the abdomen, where the 

 hatching is completed. When sufficiently matured 

 to risk an independent life, the numerous offspring 

 issue forth, and, like a pack of aquatic hounds, 

 swim in close companionship immediately above the 

 mother's head. Should an enemy suddenly attack the 

 little assembly, or other danger menace their safety, 

 then, like an immense gateway, the mother's mouth 

 spreads open, and presto, pass, in go the infant fishes, 

 slam goes the gate, and safe as in a castle with 

 drawbridge up and portcullis down, the fry lie 

 ensconced in the chest of their mother. 



The Gillbakra, a marine Siluroid, and the Zamlau, 

 from the rivers of Guiana, in a like manner swallow 

 then- families and vomit them up again on the dis- 

 appearance of danger. The latter fish is esteemed 

 a great delicacy by the natives inhabiting the districts 

 wherein it is found ; but nevertheless catching it is a 

 service of extreme danger. When hooked, the monster 

 quietly swims off with the canoe and its freight of 

 fishermen quite as easilyas a Thames tug-boat paddles 

 away with a long fleet of coal-barges ; and as these 

 rivers appear to be broken into numerous waterfalls, 

 over which the "Zamlau" does not in the least mind 

 taking a header— rather likes it than otherwise— the 

 sport, to my fancy, must be far too exciting to be 

 pleasant. 



The " Hard-back," a fish belonging to the genus 

 Callichthys, which is found along the coast of Guiana, 

 builds a regular nest of leaves and grass-stalks, 

 in holes in mud-banks not very far below the 

 surface of the water ; into these fish-nests the roe is 

 placed. The eggs once safely deposited in the nest, 

 let all fishes or other egg-loving enemies stand clear 

 of the watchful mother ; she never r goes far from 

 the nest, and is ready at any moment to do battle 

 with friend or foe, if either dares approach her sacred 

 charge. 



Sir R. Schomburgk tells us thatthesefish ascend the 

 trenches intersecting the sugar estates in spawning 

 season, where they are easily taken in baskets placed 

 near the nests. The male fish also aids in pro- 

 tecting the young. The nests are easily discover- 

 able, as above each, a little patch of froth invariably 

 accumulates on the water. The parent fishes, however, 

 often fall victims to darkey cunning, from the fearless 

 fury they display if their nests are interfered with 

 The negro places both his hands under water, and 

 gradually brings them towards the nest ; the enraged 

 fish dashes at the hands, but only to find itself 

 deftly clutched in a living trap, from which it 

 seldom escapes. 

 Another singular instance of a nest-building fish 



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