THE PECTORAL APPENDAGES OF PRIONOTUS 

 AND THEIR INNERVATION. 



ALBRO D. MORRILL. 



The Triglidae have attracted the attention of European an- 

 atomists for more than three-quarters of a century on account 

 of the remarkable finger-like processes of the pectoral fins. 

 These processes, which have proved to be free fin rays, were 

 found to be very richly supplied with nerves, and enlargements, 

 or lobes, were found on the dorsal surface of the spinal cord, 

 where these nerves united with it. 



Special efforts have been made to discover sense buds or 

 other end organs in the epidermis of these free fin rays. 



The strong resemblance to such dermal appendages as bar- 

 bels, led Merkel (i) to characterize them as wholly analogous 

 in structure and function. 



No one has hitherto succeeded in finding sense-organs on 

 these rays similar to those found on barbels, and there are 

 great differences of opinion in regard to the peripheral termina- 

 tion of the nerves in these organs. 



In the hope of settling some of these questions, I undertook 

 the study of the Gurnards found along the Atlantic coast. 



I wish to acknowledge my great indebtedness to Dr. C. O. 

 Whitman, Director of the Marine Biological Laboratory at 

 Woods Holl, at whose suggestion the work was undertaken, 

 and also to Dr. J. P. McMurrich for many valuable suggestions 

 received during the progress of the work. 



The representatives of the Gurnards found along our coast 

 are different from those found in European waters. 



Two species which are quite abundant at Woods Holl were 

 studied ; namely, Prionotus palviipcs Storer, and Prionotus evo- 

 lans Gill (14). These fish may attain the length of fifteen to 

 eighteen inches and weigh one and a half to two pounds, but 

 are generally much smaller. 



