﻿428 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 102 



many as 25. Out of about 100 examples only one (length 20 mm.) 

 has the large number attributed to juveniles of some species; in this 

 case there are 75, interrupted here and there as if hooks were being 

 shed, but the first 13 rows are intact. There are 11 or 12 tentacles and 

 the nuchal organ is conspicuous. 



A specimen with trunk 8 mm. long has 21 anastomosing muscle 

 bundles; the internal anatomy is a miniature of that of large specimens. 



Variations. — The principal variations are external and concern the 

 color, the size and shape of the larger tubercles of the anal region and 

 posterior extremity, and the introvert hooks. 



The glandular papillae are best seen in light-colored, small or 

 medium sized specimens. They form low conical eminences with a 

 blunt teatlike extremity. The circular brown portion containing the 

 platelets is the upper two-thirds of the papilla, which is delimited by 

 longitudinal and transverse shallow skin grooves forming rouglily 

 quadrilateral or roundish areas. The papillae are ordinarily separated 

 by two or three times their own diameter but in fully extended speci- 

 mens the space becomes greater. The preanal and terminal tubercles 

 are the same shape but tliree or four times larger than those of the 

 dorsum of the trunk. In very large specimens, particularly in those 

 from Humboldt Bay, the preanal tubercles become very horny, large, 

 and some of them are compressed entirely out of the original conical 

 form. These are more often seen in the darkest brown specimens. 

 The enlarged preanal papillae have the same arrangement of platelets 

 as other papillae. 



Irrespective of spotting, the skin color varies from no scattered 

 pigment (pale pinkish gray, translucent) to pale sepia modified by 

 ochraceous or yellowish tints; thence to deeper neutral or reddish 

 brown, to a dark brown (Humboldt Bay). In tide pools of Monterey 

 Bay the palest to the medium brown forms occur, but none of the 

 darkest have been found. The para types are medium brown and 

 this general tone predominates in specimens from Washington to 

 Alaska, although some fairly light examples are present (San Juan 

 Islands, Wash.; Clayoquot Sound, British Columbia; Cape Fox, 

 Alaska). The Kodiak specimens are rather darker than "medium 

 brown," and lighter than the deepest brown specimens from Hum- 

 boldt Bay, Calif. 



The 200 specimens from this locality occurred in mud of a quiet 

 bay and are all large (upward of 130 mm. long). They are about 

 half and half medium brown (often reddish) and dark umber-brown, 

 the introvert much lighter and crossed dorsally by reddish-brown 

 stripes. The integument of the trunk is thick and the skin rough, 

 coriaceous. It may be that the darker color is in part due to staining 

 by organisms in the mud. Those examined were aU females. 



