September 1, 1900.] 



KNOWLEDGE. 



213 



pattern with wliii'h to coiiipaio the iiinuinerable modifi- 

 cations presented by the order at large. But Gammorus 

 iiKiriniis on the shore and Gaminarus locusta from 

 the shore into tolerably deep water will provide 

 him with equalh' suitable standards of com- 

 parison. To the eye of the beginner these three species 

 will probably look as like as three peas, and will there- 

 fore serve him as a useful exercise in disoi-imination. 

 The amphipods that have ta.keu to life ou land are not 

 OS yet very numerous. They all belong to the Tali- 

 tiidse, a family better known as sandhoppei-s and beach- 

 fleas. These show a great and good ambition to walk 

 uprightly, but their education in the ways of sub-aerial 

 life is evidently still in progress. Many are as yet in the 

 stage of making experiments that are not always .success- 

 ful. Some, like the Talorchextia here depicted, steady 



V*- 



^i\ ).^ 



Tatorchestia tellurix, Bfitc. From Biite. 



themselves by remarkable expansions of certain joints 

 in the hinder limbs. Other devices are found in other 

 families for species that whether in or out of water 

 favour an ambulatory gait. In the open air an animal 

 that falls over on its side and can then only move on 

 by jerks and wriggles must painfully feel that, the more 

 legs it has, the more ridiriilous it looks. 



Though species of amphipods swarm in all seas, they 

 make themselves more than usually conspicuous in 

 Arctic waters. Fittingly, therefore, the earliest in- 

 telligible description of any amphipod resulted from a 

 voyage to Spitzbergen and Greenland. Friderich 

 Martens, a barber-surgeon on board a whale-ship, to- 

 ward the close of the seventeenth century, may be said 

 to have discovered them. Some of the largest and most 

 abundant of the smooth Arctic forms were described in 

 1774 by Captain Phipps, aftenvards Lord Mulgrave, and 

 some of the thorniest forms a little later by the Russian 

 writer Lepekhin. Enri/tJienes gryUus, long the cham- 

 pion gammarid. was not made known till 1822. It has 

 been found exceeding four and a half inches in length, 

 with girth in proportion. It is in colour rosy with a 

 tinge of yellow, and has its limbs aesthetically picked 

 out with vermilion. Regardless of its array, petrels 

 and sharks and other pirates swallow it without remorse. 

 Their greediness first gave it to science, for Mandt, its 

 discoverer, says, " the only specimen I brought back 

 from my journey was vomited by an Arctic petrel." 

 Sailors, aft-er their wont, angling in the air for sea-birds, 

 caught the petrel and gave it a mortal crack on its 

 skull, whereupon it disgorged the crustacean, well 

 digested, yet with the chitinous framework scarcely 

 injured. This amphipod has a vast range from north 

 to south. Also it descends through various depths to 

 the greatest reached by any species of its order. Sea- 

 birds must capture it near the surface, but whether they 

 find it there alive or dead is uncertain. In any case 

 one may still admire its powers of navigation, though 

 it no longer holds the record for size. AliceJIa gignnlea. 

 Chevreux, dredged by the Prince of Monaco in 1897 

 from a depth of 2890 fathoms, is five and a half inches 

 long, thus beating the longitude of Euryfhenes gryUu't 

 bv an inch. 



AL the beginning of this chajjter stress was laid on 

 the variability of the seven pairs of trunk-limbs. There 

 are twelve other pairs of appendages also more or less 

 variable, but here at the end of the chapter it is im- 

 possible to expatiate on the changes they exhibit with 

 their branches double or single, their joints many or 

 few, their teeth and lobes, their hooks and spines, their 

 feathers and functions. Even the eyes, which have no 

 joints at all, and which arc normally two, seated 

 laterally on the head, arc far from displaying mono- 

 tonous similarity. For, instead of two, there may be 

 four or three or one or none. They or it may be on 

 the top of the head instead of at the sides, and on the 

 projecting tip or further back. They may be compound 

 or simple. The outline may bo circular, oval, or collar- 

 like, it may be reniform, lageniform, fusiform, that is, 

 like a kidney, a flask, or a spindle, or it may be in 

 divers ways irregular. The elements may bo few or 

 so numerous as to cover almost the whole cephalic 

 surface. The colour .may be bright red or brown or 

 green or ferociously black, or again it may bo white or 

 grey or variously pallid to evanescence. There is just 

 that one point of consistency about the eyes, that they 

 are never stalked, never articulated. By a hemispherical 

 bulging they may occasionally ti-y to intimate that they 

 could gi-ow a stalk if they choose, but they never do 

 choose. 



In conclusion it may be said that persons of a fine 

 sporting instinct, who desire to be exhilarated by the 

 chance of experiencing savage nips and pinches, lacera- 

 tions, stabs and bites, will find the Amphipoda of no 

 use. Such persons must pursue the crab, the lobster, 

 the prawn, the squilla, and the isopod. Among the 

 Amphipoda there are a few species armed with strictly 

 defensive spines, but otherwise they arc of all the Mala- 

 costraca the most absolutely and universally peaceable 

 towards mankind, never intentionally inflicting upon him 

 any personal injury whatever. 



Sir John Murray and the Black Sea. 



Sir John Murray recently delivered a lecture on 

 the Physical, Chemical, and Biological Conditions of the 

 Black Sea, to the Fellows of the Royal Society of Edin- 

 burgh. The Black Sea has peculiarities which distin- 

 guish it from the Mediterranean, Atlantic or Pacific. 

 The greatest ascertained depth is 1200 fatlionis. A 

 surface current flows continually from the Black Sea 

 into the Mediterranean through the Bosphorous and 

 Dardanelles, and an undercurrent of salt water from 

 the Mediterranean into the Black Sea. This under- 

 current of water was found to be wann and to sink 

 to the bottom, and in consequence of its gr.iat density 

 prevented vertical circulation. The result was that these 

 deeper waters were rendered quite stagnant. They were 

 saturated with sulphuretted hydrogen and consequently 

 life was impossible. In an expedition in which thi 

 lecturer took part, the water brought up by means of 

 a water bottle from a depth of 300 fathoms smelt 

 exactly like rotten eggs. No life therefore is possible 

 in the Black Sea beyond a depth of 100 fathoms, which 

 was a striking contrast to what happened in the open 

 ocean, where there was an abundance of animal life at 

 that depth. This brought about another extraordinary 

 condition with reference to the deposits, viz., that in 

 all the deeper deposits there is an abundant chemical 

 precipitate of carbonate of lime, a condition of matters 

 that obtains as far as is known in no other ocean. 



