1916] Daniel: The Aiialoiivj of Hrplcuwluis maculatus 36:3 



Perforating the tei-minal parts of the girdle is a foramen throiigli which 

 the nerve passes to the pelvic fin. At the termini of the girdle are 

 the articular processes, each consisting of two protuberances which fit 

 into depressions (fossae) of the pelvic fin skeleton. These are not 

 well seen in the figure. 



Skeleton of the Unp.\ired Fins 



The Dorsal Fin. — The unpaired fins are essentially like those of 

 Heptanchus cinereus figured by Mivart (1879). In Hcptanchiis macu- 

 latiis the thin basal cartilage of the dorsal fin extends from about the 

 forty-ninth to the fifty-fifth segment of the vertebral column. From 

 this plate in Heptanchus maculatns arise seventeen or eighteen radial 

 cartilages, the anterior of which is imsegmented and the posterior 

 of w'hich is apparently a fusion of several pieces. 



The Caudal Fin. — The essential parts of the caudal fin have been 

 described (p. 360). But it nuiy be repeated that its ventral rays are 

 an integral part of the axial skeleton, being the prolongations of the 

 haemal spines. These consist of a series of rays two of which corre- 

 spond to a segment. Toward the end, however, the column is more 

 or less undifferentiated. The dorsal lobe of the fin is also supported 

 by rays which, unlike those supporting the ventral lobe, greatly exceed 

 in number the segments of the central column. 



The Anal Fin. — The liase of tlie anal fin abuts against the fifty- 

 third segment of the spinal column. The basal piece, barring the fact 

 that it is segmented in front, is remarkably similar to that of the 

 dorsal. From it, however, the radials proceed in a less definite fashion. 



Transmitted June 30, 1916. 



