248 PALAEONTOLOGY. 



the ocean at a great distance from any shore. In the North 

 Seas the clio and limacina swarm in such abundance that 

 they are said to constitute the food of the great whale. The 

 clio is provided with a singularly complex apparatus, which 

 escaped the keen eye of Cuvier, but has recently been 

 described by Professor Eschricht of Copenhagen. The head 

 is furnished with six retractile appendages, which have a 

 reddish tint, from the number of distinct red spots distri- 

 buted over their surface, amounting in each to about 3000. 

 When viewed with the microscope, each speck is seen to be 

 the orifice of a sheath which contains about twenty pedun- 

 culated sucking discs, that are capable of protrusion for the 

 prehension of prey ; so that the head of clio borealis is armed 

 with 3000 x 20 x 6 = 360,000 microscopic pedunculated 

 suckers ; an instrument which for complexity is quite unique 

 in the animal series. Clio and pneumodermon are naked 

 gasteropods, but Jiyalcsa, cleodora, and cymbulia possess shells 

 of extreme delicacy. 



From the absence in some, and the fragility of the ske- 

 letons of others, of this class, we rarely find their remains in 

 a fossil state. 



The tertiary beds of Dax and Turin contain two extinct 

 species of liyalcea. The Miocene beds of Bordeaux, tho 

 sub-apennine beds of Piedmont, and the English crag, contain 

 several species of cleodora. 



The conularia of the palaeozoic rocks is now considered an 

 extinct genus of this class. 



The CEPHALOPODA have a thick, soft, fleshy body, of a 

 spherical or elliptical form, sometimes protected by a shell, 

 sometimes naked. The mantle is a musculo-membranous 

 sheath, which encloses the digestive, respiratory, circulating, 

 and generative organs. The head is distinct from the trunk ; 

 is of a large size, and round form. It contains the organs 

 of the five senses, and those for mastication and deglutition. 

 It is surrounded by a circle of fleshy processes, or feet, from 

 whence the name of the class, " head-footed," is derived. The 

 eyes are two in number, of large size, and highly organised ; 

 and are either sessile or pedunculate. The mouth is armed with 

 a pair of vertical, horny, or calcareous jaws, which resemble 

 the bill of a parrot, and enclose a fleshy tongue, the mucous 

 covering of which develops a series of recurved .horny spines. 



