220 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



eels lists two species; Ginsburg (1951), following Jordan and Evermann 

 (1896), synonymized Ariosoma Swainson and Ophiosoma Swainson 

 with Conger and distinguished two species from the Western North 

 Atlantic. 



The specimens in the collections of the following institutions form 

 the basis of this study: American Museum of Natural History 

 (AMNH), Academy of Natural Sciences of Philadelphia (ANSP), 

 Chicago Natural History Museum (CNHM), George Vanderbilt 

 Foundation (GVF), Museum of Comparative Zoology, Harvard 

 University (MCZ), Stanford Natural History Museum (SNHM), 

 University of Michigan, Museum of Zoology (UMMZ), and U. S. 

 National Museum (USNM). 



I wish to acknowledge my thanks to the authorities of the above 

 mentioned institutions for the loan of specimens and to the following 

 individuals: Dr. L. P. Schultz and Dr. E. A. Lachner of the U. S. 

 National Museum for their kind help and advice; Dr. J. Bohlke, 

 Academy of Natural Sciences of Philadelphia; Dr. L. Bertin, Museum 

 National d'Histoire Naturelle, Paris; Dr. N. B. Marshall, British 

 Museum (Natural History), Dr. T. Kamohara, Kochi University, 

 Japan; and W. C. Schroeder, Museum of Comparative Zoology, for 

 meristic counts, measurements, and information on types deposited 

 in their collections; Dr. and Mrs. J. L. B. Smith for specimens from 

 South Africa; Dr. R. Zangerl, Chicago Natural History Museum; 

 the X-ray laboratory staff of the Federal Bureau of Investigation, 

 Washington, D. C, for radiographs used in vertebral counts; and the 

 Smithsonian Institution's photographic laboratory for numerous 

 photographs. 



Procedures: The total length and distance from tip of snout to 

 anus were taken by extending the specimens on a table and sticking 

 a pin into the table at the tip of snout, anus, and tip of caudal fin ; the 

 distances between the pins then were measured. All other measure- 

 ments were made with a vernier caliper to the nearest one-tenth of 

 a millimeter. The length of head was measured from tip of snout 

 to upper edge of gill opening; distance from origin of dorsal fin to 

 insertion of pectoral fin was measured between a line drawn from the 

 insertion of the left pectoral fin to the insertion of the right fin and a 

 vertical line was drawn from this line to the origin of dorsal fin. 

 The longest pectoral fin was measured. All measurements are 

 expressed in thousandths of total length except the distance from 

 tip of pectoral fin to origin of dorsal fin, wliich is expressed in percent 

 of pectoral fin length. Lateral line pores were counted in front of a 

 perpendicular line through anus. The pectoral rays were counted 

 after the skin was dissected from the bases of these rays, otherwise 

 the small rays at the ventral edge of the fin base might have been 



