492 PROCEEDINGS OF THE ACADEMY OF 



dorsal ; it is directed very obliquely backwards and passes slightly beyond the 

 base of the caudal; its greatest (oblique) height rather exceeds a ninth of the 

 length, and its base equals about a twentieth ; the anterior angle is broadly 

 rounded and passes much beyond the posterior; the (oblique) height behind 

 equals the base, or a twentieth of the length. 



The caudal fin is bent obliquely upwards, and its (oblique) length nearly 

 equals a fourth (24) of the total; the vertebral column is regularly attenuated 

 and disappears near the truncated posterior margin ; the elevation above the 

 lower boundary of the column is slightly greater behind the middle of the fin, 

 and equals almost a twentieth of the total length. The greatest height or 

 width of the upper caudal lobe, just before its vertically truncated end, is rather 

 less than a tenth (-09i) of the length ; its angles are rounded ; the distance from 

 the base of the lower lobe to its upper angle enters about five times and two- 

 thirds (-171) in the length; the posterior margin is slightly oblique and emar- 

 ginated; the upper angle extends rather beyond the lower; the greatest depth 

 (or width) in front of the angles is rather more than a tenth ( - 10J) of the length. 



The pectoral fin is subtriangular ; the outer margin is first curved and thence 

 is produced in nearly a straight line outwards and backwards to the external 

 angle; the posterior border is nearly straight and scarcely more produced to- 

 wards the exterior than the inner angle ; the latter is more broadly rounded 

 than the outer; the distance from the front of the base to the outer angle is 

 little less than a quarter of the length ("24^), and a fourth greater than the 

 distance from the same point to the margin outside of the inner angle (= -18), 

 or the width of the fin before the angles ("18). The fin extends almost as far 

 backwards as the posterior angle of the first dorsal. 



The ventral fins originate at the beginning of the second-fifth (40) of the 

 total length and considerably behind the vertical from the "anterior angle" of 

 the first dorsal; they are oblong, quadrangular, slightly overlapping towards 

 the middle of the inner borders, slightly emarginated and with the angles 

 equally rounded ; the length equals an eighth of the total and the greatest 

 breadth almost an eleventh. 



Scales. The scales are more or less cruciform or shaped like a Greek cross, 

 and often with each end divided. They are rather small, there being about 

 forty oblique rows beneath the attached base of the first dorsal fin. Those on 

 the inferior surface of the body and of the pectoral and ventral fins, as well as 

 the anal and caudal, are polished and more or less cordiform. 



Color. The color is brownish, varigated with sparsely-scattered, small black 

 spots on the entire body and fins. 



Family NOTIDANOIDJZ Owen ex M. and H. 



S^aUis^ 163 ParUm } Cuvier > Regne Animal > tome P- 123 < 128 )> 1817 - 

 Squalidae verse (Notidiani) Bonaparte, Selachorurn Tabula Analytica, p. 4, 1838. 

 Notidani Mutter and Ilenle, Systematise-he Besehriebung der Plagiostomen, p. 80. 

 Squalidae (Hexanchina) Gray, List of Species of Fish in British Museum. 



Chondropterygii, p. 40, 67, 1851. 

 Notidanidae Owen, Comparative Anatomy of the Vertebrated Animals, vol. i. p. 



51, 1846. 

 Notidanoidei Bleeker, Systematis Piscium Naturalis Tentamen. 

 Notidanoidas Gill, Analytical Synopsis of the Order of Squali, p. 38 ; ib. in 



Annals of the Lyceum of Nat. Hist, of N. Y. vol. vii. p. 404 . 

 Body elongated, somewhat depressed before, tapering towards the caudal fin. 

 Scales minute and generally pointed and traversed by one or three keels. 

 Lateral line present on each side of the back. 



Head depressed, oblong and semi-oval or semi-elliptical above, with the 

 snout projecting, indicated by more or less distinct constriction at the anal 



[Oct. 



