May 2, 1898.] 



KNOWLEDGE. 



105 



quantity of these Copepoda is not unwelcome. To the 

 naturalist the superfluity of this or any other single species 

 is distracting. He does not wish the novel or the rare to 

 be concealed or entangled amidst the multitudinous. At 

 times, however, numbers help to enhance the charm as well 

 as the wonder of the scene presented. Especially is this the 

 case with the genus of Copepoda called Sapphirina, concern- 

 ing which Dana says that nothing can exceed the beauty of 

 some of the species, conspicuous in single specimens, but 

 still more when they are congregated in abimdance. " On 

 account of their extreme brilliancy and rich reflected tints 

 they may be seen at great depths on a sunny day, and as 

 each becomes visible only when the position is right for 

 the observer's eye, the water seems to flash with moving 

 gems ; they even rival the richest opal and sapphire, and 

 the most brilliant combination of metallic hues." So they 

 endear themselves to the observer, and he distinguishes 

 the fascinating species as "the belle," " the rainbow," 

 " the gem," " the radiant," " the resplendent." 



There was a time when collectors deplored that on board 

 a swift ocean steamer they could not ply their favourite 

 occupation. That tantalizing era is at an end. As 

 explained in recent papers by Giesbrecht* and Herdman,t 

 small invertebrates from a few feet below the surface can 



The sea-shore is generally rich in crustaceans. It is 

 almost always far richer than might be supposed from a 

 casual survey. The common shore crab, by way of 

 exception, is an impudent, defiant creature ; but even the 

 fighting shore crab is coloured for concealment, lies low by 

 preference, and, upon occasion ofi"ered, adopts the policy 

 of scuttle. As a rule the crustaceans of the shore don't 

 want to fight — at least not with human antagonists. They 

 do not court the eye ; they make themselves small. They 

 burrow ; they hide under stones, in crevices of rock, in 

 folds of seaweed, in neat but unobtrusive tubes, built 

 by themselves or borrowed. They mimic surrounding 

 objects. They prowl about in the shells of untempting 

 molluscs. In captivity some of them change colour ; some 

 of them flounder about as if indignant. The prawns and 

 shrimps and hoppers make astounding and unexpected 

 leaps and bounds — not into the arms of the intellectual 

 observer, but in the other direction, in an unappreciative 

 sort of way. There are Tanaids and Cumacea so tiny that 

 to look for them in the sand which they inhabit is like 

 looking for a needle in a pottle of hay. These can be 

 obtained by stirring about a spadeful of the shore in a 

 bucket of water, and then pouring the water through a 

 fine net before the small animals have had time to bixry 



/C-v, 





Last uropod of the Urothoe, 

 highly magnified. 



Urothoe brevicornis (Bate). From 



North AVales. 



Second antenna of ffavstorius 

 arenarius (Slabber). 



now be easily obtained while the ship is in full career, by 

 day or by night, in tempest or in calm. The water which 

 is continually being drawn into the vessel to supply tanks 

 and baths is simply filtered through nets, which detain the 

 desired organisms. Dr. John Murray, Captain Ht-ndorff, 

 and Dr. Kiiimer are credited with having been the 

 pioneers in this method of retrieving — so facile, so fruitful, 

 so inexpensive. Thus far it appears that a large proportion 

 of the game which is bagged in this ingenious manner 

 consists of Copepoda. How great a hold these and other 

 Entomostraca have obtained on all the waters of the 

 globe, both fresh and saline, will be cons-idered hereafter 

 in connection with notes on their classification. For the 

 Copepoda in particular Mr. I, C. Thompson has recently 

 called attention to the grand economic service rendered by 

 their immense profusion at the mouths of rivers and 

 outside harbours. Transmuting the importunate refuse 

 of populous towns into their own minute forms of life, 

 they in turn become the food of larger marine animals, 

 variously adapted to gratify the palate of Lucullus, to 

 illumine his banquet, or adorn his person. 



* Abdruclc aus den Zool-jgischen Jahrliicheru, JCeunter Band, 1896. 

 tfrom Trans. Liverpool Biol. Soc, Vol. XII., 1897. 



themselves once more in the subsiding sand. The 

 ampbipod, Haustoriiis arenariiui, can be obtained in the 

 same manner, but also by simple digging, as it is a monster 

 half an inch long. It will " scriggle " in the hand, but is 

 warranted harmless. O'tfn, Lowevt-r, wlitn taken, it 

 morosely or mcdestly folds itself up, unwilling to display 

 the beauties which, were it an exotic species, would make 

 it a prize. It appears to be little known, though widely 

 distributed on the sandy shores of our islands ; and much 

 the same may be said of the species of Urothoe and 

 Bafhyporeia. 



It should be remembered that the population of the sand 

 is in general quite difi'erent from that of the seaweed- 

 covered rocks and stones, and this is illustrated in a rather 

 remarkable manner by the distinction between the sand- 

 hoppers and the shore-hoppers, although the two groups are 

 closely related. Of the rock pools it must sutfice to say 

 that, in sheltered and unfrequented spots, they are often 

 Liliputian gardens of marine zoology, from which many 

 interesting crustaceans may be gathered, either by 

 examining tufts of weed or by fishing with a fine net. 

 Diflerent forms are to be expected, according as the climate 

 of the district explored is cold, temperate, or tropical ; but 

 some species have an extremely extended and others a very 



