466 DTt JOHN ALEXANDER SMITH ON CALAMOICHTHYS, 



second dorsal spine ; 6 between the second and third dorsal spines ; 5 between 

 the third and fourth ; 6 between the fourth and fifth ; 6 between the fifth and 

 sixth ; 6 between the sixth and seventh ; 5 between the seventh and eighth ; 

 5 between the eighth and ninth ; 4 between the ninth and tenth ; and 6 shorter 

 rows between the tenth dorsal spine and the extremity of the body. 



Microscopic character of scales. — The upper surface of each scale is shining, 

 and sculptured in a manner somewhat similar to the plates of the head. 

 Under the microscope the sculpturing of the scales shows numerous flattened 

 disks, or projections of rounded outline, which are irregularly disposed towards 

 the centre of its surface, but become more regularly arranged in a concentric 

 manner towards its free margins ; the anterior and internal beveled margins of 

 the scale being nearly smooth. With a stronger microscopic power, the surface 

 exhibits the raised and rounded portions alternating towards the margins, with 

 intervening narrow and cylindrical-like projections, radiating outwards. The 

 whole surface of the scale is found to be also covered with minute perforations 

 or pores, apparently communicating with the cellular interior of the scale ; while 

 interspersed among these pores, there occur a smaller number of perforations or 

 pores, of a larger size. (Fig. 6.) 



I am indebted to my friend Mr Charles W. Peach, the well-known naturalist, 

 for the correct and careful drawings exhibited, which display these various details 

 in the arrangement and structure of the scales. (See Plate XXXII.) 



Lateral line. — The lateral line of the body is shown by a series of small 

 mucous pores or openings, which appears in the scales (about the third, or fourth, 

 from the mesial line of back), and runs in a line from behind the posterior 

 angle of the operculum, to the middle of the caudal extremity. Occasionally, 

 one or two scales in this line are apparently passed over, having no pores on 

 their surface ; and the series then goes on again after this interrupted manner ; 

 sometimes, however, the pores appear in the scales immediately over those 

 in the line which appear to be passed over. Besides these pores, there are 

 various others scattered apparently among the scales over the upper parts of 

 the body of the fish, and occasionally even in the median scales of the back. 



The fins. — The fins generally are small in proportion to the size of the fish. 



The Pectoral fins arise immediately below the operculum, and are obtusely 

 lobate in character, being connected to the body by a pedicle or arm-like process 

 (as in Polypterus), which terminates in a gently curved distal extremity, from 

 which the fin-rays spring, to form a rounded fin — the central rays being the 

 longest. The base of the pedicle is covered on its external surface with small 

 ganoid scales, apparently laid simply side by side, in rather irregular rows; these 

 terminate in a nearly straight line across the middle of the pedicle, leaving 

 an oval space bare, or free from scales, at the base of the fin-rays ; the scales 

 at the edges of the pedicle, however, pass backwards to the base of the fin-rays, 



