178 THE PEARLY NAUTILUS. 



the nautilus, from the analogous organs in the ordinary 

 cephalopods, that a particular notice of them is re- 

 quired. The first thing which strikes the observer is 

 their great number ; the next^ their want of sucking 

 discs. Descending to particulars, it is to be remarked, 

 as Professor Owen states^ that the hood covering the 

 head is thick, and of a triangular form, with an anterior 

 orifice ; its upper part is wrinkled and covered with 

 papillse, and from its sides are given off numerous round 

 tapering processes : these are nineteen on each side, 

 or thirty-eight altogether ; but, as the hood itself consists 

 apparently of two very broad digitations conjoined along 

 the mesial line, twenty pairs (in all forty) of these late- 

 ral appendages may be enumerated. Each of these 

 appendages consists of a longitudinal canal, in which 

 is lodged an annulated tentacle, about two inches and 

 a half in length, and capable of being protruded from 

 its sheath (see the figure on p. 179, representing the 

 sheath opened). In the specimen dissected by Pro- 

 fessor Owen, some of these tentacles emerged to the 

 extent of half an inch from their sheaths ; the others 

 were retracted, and did not reach the aperture of the 

 sheath by a quarter of an inch. Besides these forty 

 tentacula, are four others of a different structure, be- 

 neath the margin of the hood^ one before and one behind 



