292 A HISTORY OF RECENT CRUSTACEA 



eight families, together containing twenty-five or twenty- 

 six well-defined genera, and about a hundred and eighteen 

 satisfactorily determined species. In certain localities the 

 extreme abundance of some of these supplies a welcome 

 food to shoals of herring. In size and number of indivi- 

 duals the Arctic species appear to excel all others. It is 

 probable that many forms still remain to be discovered, 

 since up to 1876 a single species obscurely described from 

 the Black Sea was the sole representative of the sub-order 

 in the area of the Mediterranean, where in the winter of 

 1876 Professor Sars found no less than twenty-three 

 species, of which fourteen were new to science. Before 

 1859 none were known from the waters of the Clyde, and 

 in these Mr. David Robertson, of Cumbrae, has since 

 found fifteen species. 



Among the curiosities of scientific literature are the 

 disputes which have occurred actually within the last fifty 

 years, as to whether the Cumacea did or did not possess 

 organs of vision, and as to whether they were or were not 

 merely larval forms. The well-known and diligent ob- 

 server, Colonel Montagu, at the beginning of the century 

 found in South Devon a species which in fact possesses 

 sight, but not unnaturally Montagu did not attempt to 

 discover the creature's eye, because he was under the 

 " impression, though an erroneous one, that his solitary 

 specimen had lost its head. Kroyer, many years later, 

 happening to meet with various species which are in truth 

 blind, formed the opinion that all the species were so, and 

 that eyes had been attributed to some of them under an 

 illusion. Harry Goodsir, a Scotch naturalist, in 1843 

 published the remarkable statement that the eyes are 

 'pedunculated but sessile.' He lost his life not long 

 afterwards in Franklin's Arctic expedition, and left his 

 opinion to be for many years doubted, denied, or sup- 

 ported, without its being in his power to explain that 

 what he obviously intended to print was that the eyes 

 were 7iot pedunculated but sessile. It is probable that 

 Kroyer was completely mystified by the misprint. ' Good- 

 sir,' he says, 'thought that eyes must be found in the 



