50 SALPID^.. 



tlividual produces an aggregate assemblage, and each of tlie 

 members of sucli a group produces isolated individuals. 

 The members of the one generation are very dissimilar from 

 those of the other ; consequently specific names have been 

 doubly multiplied. 



The recently published observations on Sal2)a: by the 

 Norwegian naturalist, Sars, one of the most original and 

 philosophical of living zoologists, have thrown great light on 

 the habits and development of these curious creatures. 

 They are to be found in the first part of his beautiful 

 " Fauna littoralis Norwegh-c,*'"' and should be carefully 

 studied by the British naturalist who may be fortunate 

 enough to meet with our native species. 



Sal2>^ were first observed in the British seas by the 

 eminent geologist, Dr. JNIacculloch. His account of them 

 is given in his work on the Western Islands, in that part 

 which relates to the natural history of Jura.* It is accom- 

 panied by a very rude figure, insufficient for the determina- 

 tion of the species, but putting the genus beyond question. 

 The description which the doctor there gives is so interest- 

 ing and original, that we think it right to extract it entire 

 in his own words : — 



" Some marine animals occur in these seas which remain still 

 unrecorded in the catalogue of British zoology. Among these, 

 indeed, it is probable that a few will be found still uiidescribed 

 by naturalists, since fresh additions are even yet occasionally made 

 to our catalogue of these obscurer parts of the creation. Many of 

 these animals have occasionally fallen under my notice, but amid 

 pursuits which rendered it impossible to attend either to their exa- 

 mination or preservation. I have, however, preserved a memorial 

 of one, as it appears to form a new species in a tribe of which no 

 individual has yet been observed within the limits of the British 

 seas. It belongs apparently to the genus Scdpa, and the accom- 

 panying drawing would be sufficient to distinguish it, even with- 

 out a specific definition. f 



* Western Isles, vol. ii. p. 187. t Plate 29. 



