1910.] AND NUDIBRANCHS OF BERMUDA. 139 



from the olive to orange colours, and the under edge of the mantle 

 is generally so. The number of streaks and mottles is not 

 constant. About 5 mm. back from the rhinophores and a little 

 nearer the median plane, there are two oval spots of light blue, 

 which are constant in position but not in shape nor in relation to 

 the streaks. 



The tentacles are short, retractile, conical, and blue in colour. 



The rhinophores are perfoliate with 28 leaves in the clavus. The 

 clavus is of a deep ultramarine blue, the deepest colour seen any- 

 where on the animal. The rhinophores may be retracted within 

 conspicuous collars, which have smooth margins. 



Text-ficv. 7. 



Chromodoris zebra Heilprin. 



Viewed from the right side ; the branchial rosette turned toward the observer, 

 f natural size. 



The branchiae are from 12 to 14 in number ; they are surrounded 

 by a high sheath with a smooth margin, within which they are 

 completely retractile. In the olive-coloured forms the branchiae 

 are often more deeply coloured than the mantle, and in such 

 forms the backs of the plumes are slightly bronzed. The more 

 orange-coloured individuals have light coloured branchiae, which 

 are frequently lighter in colour than the mantle. The branchiae 

 when fully expanded are rosette-like in outline and extend beyond 

 the tody. When in this expanded state, one readily notices an 

 inner flesh-coloured collar that expands beyond the limits of the 

 mantle-collar. The anal opening is subcentral, the ring formed 

 by the t bases of the branchiae being open on the posterior and 

 ventral margin. The tip of one or two of the branchiae is seen 

 to end in a minute division into two, three, or four parts. This 

 is a very common characteristic, so that one hunts for some time 

 before finding an animal which does not show it ; only two such 

 specimens were noticed. The gills occupy both sides of the plume 

 as a series of about fifty leaves. 



On the ventral, posterior border of the mantle there are five or 

 six white conical elevations, which produce the beaded effect 

 mentioned by Heilprin. The whitish colour is due to the presence 

 of numerous globular structures, which turn pinkish in strong 

 nitric acid. They were not destroyed, nor was there any 

 effervescence, in nitric or hydrochloric acids. These white conical 

 papillae are noticeable in the living animal, but become more 

 conspicuous after the animal has died. 



The mouth is circular. 



