Prof. Owen's Description of the Lepidosiren annectens. 329 



the snout, and gradually increasing to the height of five lines, is thus continued 

 into the caudal membranous expansion. This fin is supported by numerous 

 soft, elastic, transparent rays articulated to the extremities of the superior and 

 inferior peripheral spines of the caudal vertebrae : the under part of the caudal 

 fin commences about one inch behind the vent. 



The entire body is covei'ed with cycloid scales*, which are relatively larger, 

 but have the same general structure and disposition as in the Lepidosiren 

 paradoxa. They present a subcircular form, with a diameter of about three 

 lines ; their posterior margin adheres to the strong cuticle, with which they 

 are removed as in other fishes: the anterior margin lies freely in a correspond- 

 ing groove of the chorion. When viewed with a low magnifying power they 

 present a series of canals, radiating somewhat irregularly from a centre near 

 the posterior edge of the scales, and maintaining a uniform diameter. These 

 canals are united together by cross canals, which do not form regular con- 

 centric lines. The meshes formed by this reticulation are small and of a sub- 

 quadrate form at the anterior part of the scale, but are more elongated in the 

 middle of the scale : they are, again, smaller and shorter at the circumference. 

 With a magnifying power of 150 linear diameters the interspaces of the larger 

 canals are seen to be occupied by a finer network of apparent tubes, and 

 from an angle of each of these spaces a short obtuse process, projecting 

 slightly backwards, is developed on the external surface of the scale : the 

 internal surface is quite smooth. There are three or four faint concentric 

 lines of growth at the circumference of the scale, but this body is evidently 

 one continuous organized whole. The subcuticular tissue of the scale is a 

 kind of dense elastic cartilage, not yielding any gas-bubbles on the application 

 of acid. The scales are continued upon the base of the caudal natatory fold 

 of integument. 



The disposition of the mucous pores and ducts upon the head is very similar 

 in the two species of Lepidosiren, judging from the figure given by Dr. Nat- 

 terer. A linear series of mucous pores encircles each eye, and from the pos- 

 terior angle of this series the lateral line commences. This line extends 

 backwards, neai'ly parallel with the dorsal line, situated a little more than 

 one-fourth of the vertical diameter of the body from that line, until it nearly 



* See the magnified view of one of these scales. Tab. XXVII. fig. 1. 



2x2 



