LANCELET. 



mouth as seen from below, with the filaments from cacli side 

 stretching across the opening ; the outline on the left of the 

 middle is a magnified view of the two portions of the hyoid 

 or lingual bone, to which the filaments are attached, one 

 branch of which bone is divided, and the cut portions 

 turned up and down to expose the other perfect side ; the 

 figure at the base is a magnified view of the appearance of 

 the whole fish. 



Several relations in structure to the Lampreys and Myx- 

 ine are observable, namely, the fringed mouth, the armed 

 lingual bone, the absence of eyes, the want of pectoral and 

 ventral fins, the investing tunic, and the tough, but flexible, 

 internal dorsal column. Of its habits, that which has been 

 stated is known : it is extremely active when in water, and its 

 food is probably some of the most minute among the thin- 

 skinned Crustacea, or decomposing animal matter. 



It may perhaps be expected that I should state on what 

 grounds I have ventured to differ from such a naturalist 

 as Pallas in considering this animal a fish, and not a Limax, 

 It is distinguished from the Limaces by the absence of the 

 ventral muscular disk for locomotion ; and from every other 

 molluscous genus, in the position of the anal aperture, which 

 is unconnected with the respiratory cavity. On the other 

 hand, the dorsal fin, and regular oblique strata of muscular 

 fibres clothing the sides of the body and having their points 

 of origin attached to a firm dorsal internal axis, with the 

 existence of a lengthened internal vertebral column, although 

 in a soft cartilaginous state, as in the Myxine, are sufficient 

 to determine the primary division of animals to which the 

 Amphioxus belongs. 



The publicity given to this little animal, which appeared 

 not to have fallen under observation since the time of 

 Pallas, and the situation claimed for it, in the first edition 

 of the History of British Fishes, have led to many satisfac- 



