684 SIR c. ELIOT ON NUDiBRANCHs [June 19, 



LiNGUELLA FALLAX (?) Bergh. 



(Bergh, " Beitr. zur Kenntniss der japaBischeii Nudi- 

 branchien," Vei'h. k.-k. zool.-bot. Ges. in Wien, xxx. 1880, 

 pp. 177-180.) 



Three specimens are possibly referable to this form. Con- 

 sidering their age they are well preserved. The dorsal surface, 

 gills, side-lamellfB, and foot are all brownish pink ; the mantle, 

 foot, and tentacular shield are bordered with yellow, and the 

 rhinophores are tipped with the same colour ; the dorsal surface 

 bears 15-20 yellow longitudinal stripes, with indications that 

 there were narrower stripes between them which have disappeared. 

 Under the lens it is seen that some of the stripes are composed of 

 a series of minute yellow rings. The largest specimen is about 

 40 mm. long (but much bent) and 16 broad. 



The dorsal surface is smooth, except that some of the stripes are 

 distinctly raised, and is continuous with the smooth tentacular 

 shield, which is not very wide and not much produced at the ends. 

 The central dorsal stripe passes between the rhinophores and 

 beyond. The gill is a tightly-packed collection of lamellre, which 

 lie not in a cleft, but between the body-wall and the mantle-edge. 

 Immediately behind the gill there is in all the specimens a large 

 lobe (as much as 5 mm. x 3 mm.), and in one there is a smaller 

 accessory lobe on the left side. The side-lamellie are numerous 

 and thick, not so well preserved as the rest of the animal, but 

 seemingly fan-shaped. The largest is 4 mm. long and 2 mm. 

 broad at the tip, but narrower at the base. The penis projects in 

 front of the gill. It is about 5 mm. long, cylindrical, slender, and 

 unarmed. No cnidopores were found. 



The jaws are yellow, not very strong, with 6-8 rows of mosaic-like 

 denticles. In the two specimens opened, the radula consisted of 

 55 and 60 rows of teeth respectively. In the smaller radula the 

 number of laterals did not exceed 17 or 18, in the larger it rose 

 to 21. The rhachidian tooth is very broad, and bears 10 denticles 

 on each side of the central cusp. The fii'st lateral does not overlap 

 it much, and is not very markedly different from the succeeding 

 teeth, though stouter and more hamate. The first four laterals 

 bear eight denticles. The rest are smooth and erect, but the fifth 

 sometimes bears one or two denticles. After the fifth no denticles 

 were seen. 



In most of their external characters and in their buccal parts 

 these specimens agree with L. fcdlax, described by Bergh from a 

 single specimen found at Enosima, Japan. Bergh, however, 

 mentions no dorsal stripes, and it is remarkable that they should 

 have disappeared in a comparatively recent specimen and lasted 

 so long in those kept at Newcastle. Also, although the radula is 

 essentially the same as that described by Bergh, the central tooth 

 is wider than in his figure. The identification must therefore 

 remain somewhat doubtful until more Indian and Japanese 

 specimens can be compared. 



