100 bulletin: museum of comparative zoology. 



snout, which is white; intestinal region deep flesh 

 color or pale red, or yellowish when sexual products 

 are mature; accessory biiccal glands wanting. 



M. (jriffini, p. 188. 

 o. Salmon or flesh color (rarely light, rosy brown); shad- 

 ing into lighter, with tinges of brighter red, or nearly 

 white anteriorly ; intestinal lobes more deeply col- 

 oi-ed, sometimes brown ; a cream-colored stripe is 

 situated in median ventral line ; accessory buccal 

 glands well developed . . M. aluskensis, p. 187. 



cc. Color olive, ochre or buff; ocelli present. 



1. Pale olive brown, grayish ochre or butt'; deeper brown in 



intestinal region , and with a paler median dorsal stripe 



in esophageal region ; (5 to 12 or more small black 



ocelli in an irregular row or elongated cluster on each 



side of head .... ]\f. olivnris, p. 181. 



EE. Body usually long and ribbon-like, much flattened, with 



very thin lateral margins ; well adapted for swimming; 



dorso-ventral and diagonal muscles well developed; neu- 



rochord cells present in many species. 



Cerebratui.us, p. 191. 

 a. Snout whitish both above and below, strikingly ditt'erent 

 from deep color of body. 



1. Body very long and ribbon-like, attaining a length of 



more than two meters ; deep blood red above and 

 below, except tip of snout, which is yellowish white. 



C. niontfjo/iifiri/i, p. 200. 



2. Body long and ribbon -like, very dark brown or reddish 



piirple, except head, whicli is wliite on both dorsal and 

 ventral surfaces, back about tlu'ee -fourths the length 

 of the ceplialic furrows, or sometimes nearly or quite 

 to the mouth . . . . (_'. (i/bifrons, p. 198. 



aa. Snout not strikingly dift'erent from body in color . b. 



b. Without distinct longitudinal or transverse markings on 



body ........ c- 



c. Color of body black, brown, reddisli brown, olive or 

 dark gray, sometimes with paler lateral margins d- 

 d. Body long and rib] ion-like. 



1. Color slaty brown to grayish or pale olive, paler 



beneath, and often with conspicuously jialer or 

 white lateral margins . ( '. niarf/inatus, p. 193. 



2. Color dark brown or purplish, paler on borders 



of cephalic furrows and tip of snout: head and 



