396 The Lobster ; Its Structure and History. (July, 
Considering the wide and even tropical distribution of V. cardui 
in the Old World, its absence from South America seems not a 
little remarkable. But the species of cosmopolitan genera not 
very rich in species (like Vanessa) are generally conterraneous, 
or they occupy adjoining zodlogical provinces as equivalent species, 
species of replacement, or, as the Germans sometimes call them, 
vicarious species. But we have already seen that, if we leave out 
of account our cosmopolitan species, and restrict V. Atalanta to 
the Old World, where it actually belongs, each of the species of 
Vanessa occupies a separate zodlogical region, one adjoining an- 
other, over nearly the entire extent of either world. The cosmo- 
politan species, similarly restricted to the New World as its 
proper habitat, occupies nearly the same region as V. Huntera, 
extending no doubt farther north, and becoming less abundant 
toward the southern extremity of the common limits of the two, 
phenomena which are repeated in the distribution of our two 
common and wide-spread eastern species of Argynnis, A. Cybele, 
and A. Aphrodite. The absence of Vanessa cardui from South 
America is therefore rather an argument in favor of its Ameri- 
can origin. The presence of the insect on the shores of Behring’s 
Straits, as testified by Wagner, is an indication of its route from 
America to Asia; and this passage must have taken place in 
times so far distant that it has had opportunity to push its way 
even to Australia and New Zealand, and there to become so mod- 
ified as to establish a peculiar race, once dignified by a specific 
name. If its presence in the Hawaiian Islands can be prove 
such a fact would be more difficult to understand ; but we can 
hardly doubt that V. Tammeamea and the other Old World 
species of Vanessa sprang from: one original stock ; and if the 
progenitors of the Hawaiian Islands species found a track from 
the Asiatic continent, so, plainly, could Vanessa cardui. 
THE LOBSTER; ITS STRUCTURE AND HISTORY. 
BY J. 8. KINGSLEY. 
AS the season of summer schools is approaching, it has e 
thought advisable to give a short account of the anatomy o 
the lobster. This animal has been chosen not only on account of 
its size and the ease with which either it or its fresh-water cousin, 
the crayfish, can be obtained, but also from the intermediate 
position it occupies in the articulata, forming an important SYP 
of this branch of the animal kingdom. A few technical terms 
