290 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



RHACHIANECTES GLAUCUS COPE. CALIFORNIA. 



These measurements are so little in accord that new observations are very 

 much to be desired. 



WHALEBONE. 



The larger portion of the whalebone of one side of the mouth, from a speci- 

 men taken at San Luis Obispo, Cal. (No. 23306, U. S. N. M.) was sent to the National 

 Museum by Mr. C. H. Townsend. This whalebone is entirely yellowish -white, 

 both blades and bristles, except at one end of the series. Here for a distance of 

 about 8 inches the blades and bristles are dull chocolate-brown. The end-blades 

 are entirely brown, the next have some white on the inner side, then follow a 

 number brown on the outer edge only, and finally all white, like the majority of 

 the series. The blades are very thick on the outer margin, with a rounded edge. 

 The largest plates measure 18 in. in length without the bristles, and 6 in. at the 

 base. The longest bristles measure 9 in., and were perhaps originally a little 

 longer. 



OSTEOLOGICAL CHARACTERS. 



The skeleton of Rhachianectes has been described in more or less detail by 

 Ball (26, 226-227), Van Beneden (6), Malm (7) and Beddard (8, 168). 



There is a skull in the National Museum (No. 13803) which Mr. Dall obtained 



' From end of mandible. * From length of mouth. ' From chin to eye. 



