REVIEWS, 2 1 



the prehensile antennas are freed from their cases ; the two eyes stand further apart; 

 the three posterior pairs of legs have been developed, and a small abdomen has be- 

 come distinctly separated from the thorax. When the due time for the act of 

 the metamorphosis has arrived, the pupal carapace splits along the dorsal edge and 

 is cast off, together with the acoustic sacks, the basil segments of the two antennas, 

 and the great, black, compound eyes, hanging to the UU-like apodemes. The ex- 

 uviae usually continue for a time united to the cemented antenna, but are finally 

 washed away." 



We need hardly say that the above extracts are only a tithe of the 

 account given by the author, which extends over many pages, and that 

 in several species slight modifications occur. We have a long account of 

 the structure of the shell and of the anatomy of the various parts of the 

 body of the Cirripede. In speaking of their nervous system, we have 

 some interesting remarks on their sensitiveness, which we subjoii 



" I found the following three species viz., Balanus balanoides, B. crenatus, 

 and Chthamalus stellatus very sensitive to shadows that is, to an object like my 

 hand, passing even quickly, and at the distance of about a foot between them and 

 the source of light. They were indifferent to a gradual change from bright to ob- 

 scure light ; but instantly perceived and drew in their cirri, when my hand was 

 passed between the basin in which they were kept and the window, even when this 

 was tried rather late on a dusky evening, and, likewise, when my hand was passed 

 between them and a single candle. I took, of course, the precaution of passing my 

 hand in other directions, but this never produced any effect. These species are 

 moderately sensible to any vibration in the vessel in which they were kept, but they 

 were indifferent to noises made in the air, or in the water. I found it impossible 

 to touch, under water, an individual shell ever so lightly with a needle without all 

 the immediately surrounding individuals, when several adhered together, perceiving 

 it and retracting their cirri ; it made no difference whether the one touched had 

 withdrawn its cirri and was motionless. From this fact, and from seeing that a simi- 

 lar, but slighter effect was produced by touching the rock on which the specimens 

 adhered, I infer that the perception by the others of the one being touched, is com- 

 municated by vibration. When an individual was touched under water, not by a 

 needle but by a pointed camel-hair brush, it generally withdrew its cirri ; but the 

 neighbouring specimens took no notice ; when touched by a single hair of the brush 

 no notice was taken, unless the skin of the orifice leading into the sack was so 

 touched." 



With respect to the geographical range of this sub-class, the results 

 arrived at have no very peculiar interest, owing to the species not being 

 sufficiently distinct, and, what is still more adverse, the genera, with unim- 

 portant exceptions, range over the world. Sessile Cimpedes are found in 

 every sea, from lat. 74 18' north, to Cape Horn. Mr. Darwin divides 

 the globe into four provinces arid one sub-province. First, the North 

 Atlantic Province, to lat. 30 north, contains 31 species, of which 22 are 

 confined to the province ; if the West Indies be included, the numbers 

 will be 42 and 28. Second, sub-province of South Africa, total number 

 of species, 11 ; peculiar to the province, 5. Third, second province, west 

 coast of North and South America, total number of species, 22 ; peculiar, 

 15. Fourth, third province, East Indian Archipelago, total number, 37 ; 

 peculiar, 24. Fifth, fourth province, Australia, total number, 30 ; 



