May 1, 1SG0.] 



SCIENCE-GOSSIP. 



101 



oddities, the hippocampus possesses the power of 

 moving each straw-coloured eye independently of 

 the other. Watching their comic faces, it is hard 

 to divest one's self of the idea that they are 



" making eyes " at you, so constantly do they roll 

 and twist them about in opposite directions. If fish 

 had pantomimes, the hippocampus as clown, if he 

 could only wink, Mould make a certain fortune. The 

 male, as in the marsupial pipe-fish, has a regular 

 egg-pouch placed under the tail, formed by a 

 doubling of thick skiu, with an opening at the com- 

 mencement only. The female has no pouch. The 

 ova are contained in the abdomen of the female, 

 similar to ordinary fishes. The mode of transferring 

 the ova from female to male is unknown (I believe). 

 Most probably it is accomplished as in other Syn- 

 gnathi. 



The worm pipe-fish, as previously observed, 

 exhibit in their embryonic condition a remarkable 

 similitude to the Batrachia (Gr. bat radios, a frog) 

 in throwing off a portion of their bodies, on attaining 

 a more advanced stage of development. But what 

 shall we say to the extraordinary system for egg- 

 carrymg and hatching, found to exist in the females 

 oiAspredo batrachus ? This genus, the genus Aspredo, 

 contains several " odd fishes," belonging to the Silu- 

 roids which also take care of their progeny, that we 

 shall refer to more at length in a future chapter. 



The Plpa Americana, or Surinam Toad, has been 

 long known as a most remarkable example of repro- 

 duction. If the female is carefully examined at the 

 breeding season, an immense number of singular 

 pits are discoverable, completely covering her back. 

 The habit of the female is to deposit her spawn on 

 the margin of some pool or stream ; but the male, 

 after his paternal visit to the ova, instead of alon- 

 ing, collects the whole mass, and manages, by some 

 means, to get them upon the back of the female. 

 "When this is accomplished, a single egg is pressed 

 into every cell, which closes with a kind of lid. In 

 these cells the development of the embryo takes 

 place, in the same manner as the free larva? of 

 Batracliians generally. The tadpole is a familiar 

 example. 



Dr. Gunther * says :— " If the pouches on the back 

 of the pipa were shallowed to mere impressions, and 

 the walls between them severed into flaps, we should 

 have the same arrangement as in Aspredo'' This 

 extraordinarily anomalous system of fish-hatching 

 I shall endeavour to more fully explain in my next 

 communication. 



J. K. Lokd, E.Z.S. 



" When, amidst the solemn stillness of the woods, 

 the singing of joyous birds falls upon the ear, it is 

 certain that water is close at hand."— Livingstone's 

 " Zambesi." 



* Cat. B. M. Fishes. 



DESMIMACE^. 



A ETER the slides purchased with a microscope 

 -*-*- have been looked at, and such novelties as are 

 to be found in the house, which beginners invariably 

 make their first inquiries about, viz., a human hair, 

 the edge of a razor, cheese mites, &c, have likewise 

 passed in review, the buyer comes to a stand-still. 

 How the objects are prepared he has not the least 

 idea; he admires their beauty when mounted, 

 but comes to the conclusion that a good collection 

 is too expensive for him to indulge in. The re- 

 sources of the instrument, and the mysteries of 

 Canada balsam, that pons asinorum of young micro- 

 scopists, are as yet unknown ; so he carefully puts 

 his purchase away, aud there it remains, till some 

 energetic friend gives his microscopical curiosity a 

 new stimulus. 



The first suggestion some one who sees his posi- 

 tion makes, is that some of the water out of a pond 

 be procured, and he perhaps offers company and 

 experience in getting it. Accordingly, away they 

 go together, and bring home sundry bottles of a 

 most uninviting-looking mixture of mud and water, 

 on which none but the initiated would set any value 

 whatsoever. 



A quarter of a minute's instruction in the use of 

 the dipping-tube makes our young microscopist 

 quite expert in depositing a small drop of the 

 lighter sediment on the animalcule cage, and sub- 

 mitting it to inspection. 



Conspicuous among the numerous objects passing 

 under notice will be certain green bodies, of various 

 sizes and shapes, sometimes symmetrical, sometimes 

 fantastic, but always beautiful; and these he will 

 be told are Besmidiacea, or, for shortness, desmids. 

 We suppose the gathering to be made anywhere in 

 the country, either from rivulets, ponds, clean 

 ditches, or footprints of cattle in bogs. 



Eor the benefit of beginners, we offer a few 

 remarks from our own experience with these minute 

 organisms, corrected, so far as we are able, by 

 reference to the authorities on the subject. 



They may be gathered in great profusion at 

 Keston, and also, so Mr. Hogg says, near Tunbridge 

 Wells. We mention these places only, because, 

 being near London, they are convenient collecting 

 grounds for our town students — the habitat of 

 desmids being, in fact, everywhere. 



They all consist of a transparent envelope or case 

 ( sometimes filamentous and attached, but often 

 free), containing green colouring matter called 

 endochrome or chlorophyll ; are beyond a doubt 

 vegetable iu their nature, though very iow in 

 organization; are useful aud important agents in 

 the conversion of the septic conditions in stagnant 

 waters into healthy oues ; aud furnish food to 

 myriads of animalcules and small aquatic larvae, 



