Notices of New Books. 4825 



Mr. Spence Bate's paper on the Function of the Antennae in 

 Crustacea is highly interesting: after describing these organs with 

 some care, he thus continues : — 



"The next question which we have to consider is, to which sense 

 either of these two sets of organs belongs ; whether the upper belongs 

 to the auditory and the lower to the olfactory, as I shall endeavour to 

 prove, or vice versa, as maintained by Prof. Milne-Edwards. 



" We shall divide the evidences on either side under two heads ; 

 the first, that which is derived from an external observation ; and the 

 second, that which is derived from its internal organization. 



u First, then, from external circumstances : an auditory apparatus 

 is an organ furnished to an animal for one or both of two objects; 

 first, for protection from danger ; secondly, for the pleasure derivable 

 from sounds. To animals so low in the scale of beings as the Crus- 

 tacea, placed as they are in a medium which must considerably 

 modify its character, sound can convey little to the consciousness of 

 the animal beyond a sense of security or danger. 



" To enable this to be of the most extensive value, the auditory 

 organ must [be] and always is so placed as to be most exposed to 

 external impressions at all periods; particularly when the animal is 

 at rest or pre-occupied. 



" Now if we look at the organ the present state of science attri- 

 butes to the sense of hearing, we find that, in the most perfectly 

 formed animals, the Brachyura, it is enclosed within a body case, and 

 secured by a calcareous operculum; that it always is so in a state of 

 rest, and only exposed when especially required. Not only is this the 

 case throughout the order, but, in some genera, as Corystes, Cancer, 

 &c, it is again covered by the supplying organs of the mouth. 



" If we take into consideration that the inferior antenna is frequently 

 developed into organs assimilating to feet, and frequently used for the 

 purpose of assisting to climb, &c, it seems difficult to admit that it is 

 an organ capable of protecting the animal by its quick detection of 

 the sound of approaching danger. 



" If we turn our attention to the superior antenna, we find that 

 in the living animal it is always elevated in the water and never at 

 rest, — always playing with a constant vibration and a jerking motion 

 peculiar to itself in the higher orders. Among the Amphipoda, 

 though constantly erect, the motion is more regular and graceful; 

 this probably is consequent upon the greater relative length of the 

 organ. 



" This organ is one that appears as if always on the watch ; let the 



