Notices of New Books. 4827 



observed, the first or basal articulation is largely developed : if it be 

 removed from its connexion with the animal, and broken open, the 

 basal articulation will be found occupied by a still smaller chamber, 

 having calcareous walls of a much more delicate character than the 

 integumentary structure. This internal chamber or cell is that which 

 in this paper is supposed to be a cochlea, from its analogy, both in its 

 structure and supposed use, to that organ in higher animals. It is 

 situated in the cavity of the basal articulation of the antenna, and 

 attached to the walls furthest from the median line of the crab. It 

 presents a tendency to a spiral form, but passes not beyond the limits 

 of a single convolution. The calcareous walls extend across the axis 

 of the ideal spire, and the internal cavity is one continuous irregular 

 chamber, the walls of which, at the centre of the axis, closely 

 approximate so as almost to meet. 



" This internal cell represents, we think, the cochlea of higher 

 animals, to which it bears some resemblance, both in form and 

 structure. If so, then beyond dispute it identifies the superior 

 antenna as an organ of hearing. 



" The internal structure of the inferior antenna differs very 

 materially from the appearances we have just described. In the 

 Brachyura, where the organs are most fully developed, there is 

 attached to the operculum a long osseous tendon or lever, by which 

 the attached muscles raise or close the entire organ, but there is no 

 internal structure of any kind which could identify it as an organ of 

 sound. The aqueous sac mentioned by Edwards 1 have entirely 

 failed to discover. 



"Viewing the two antennas each as a whole, in their relative 

 positions and connexion with the rest of the animal, we are forcibly 

 led to the conviction that the upper antenna is an organ of hearing 

 and the lower antenna is an organ of smell." 



I am desirous of giving every publicity in my power to this 

 ingenious hypothesis, diametrically opposed, though it be, to my own 

 convictions on the subject. 



Mr. Thompson's note on Nereis bilineata is as follows : — 



" I beg to draw your attention to a fact I have not seen noticed in 

 print. It is, that Nereis bilineata constructs a tube for its domicile. 

 Its usual habitat is the upper coils of any dead whelk that may have 

 been selected by a Pagurus for its domicile. This annelid is well 

 known to the fishermen here, by whom it is much used as a killing 

 bait for whiting. I was not aware of the fact of its constructing a 

 tube for itself until lately, when, on breaking off the top coils, I found 



