372 NOTES ON SOME BKITISH NUDIRRANCHS. 



which is ahiiost invisible in many specimens. The cerata are set in from 

 nine to twelve rows, the most conimoii munher heing ten. Each row 

 contains two or three cerata, more rarely four. Tlie stalk or common hase 

 on which they are set is not at all conspicuous, but when an attempt is 

 made to <letach them they come off in twos or threes, and not separately. 

 They are not at all caducous. Tn most specimens they are oblong-ovate 

 in shape; hut in two (as in Alder and Hancock's figures) thoy are 

 cylindrical. The tentacles and rhinophores are hoth small, without a 

 trace of perfoliations. 



The jaws are thin, smooth, and colourless. The radula consists of a 

 colourless, continuous ribbon, l)ent into a roughly semicircular shape 

 (Fig. 20.), and bearing 60-100 denticulations like the teeth of a saw, and 

 gradually increasing in size.* No trace of any loose, detached teeth was 

 found. The oesophagus leads into a dilatation (Fig. 21. d.) of moderate 

 size, which may be called the stomach. From it extends a diverticulum 

 on either side which supplies two cerata. Posteriorly the stomach is 

 prolonged into a very wide sacculated gut (Fig. 21. a.), which extends to 

 the extreme end of the body and gives off simple diverticula, each of which 

 supplies a single group of cerata. These diverticula fill the cerata 

 entirely, and no cnidocysts were found. The contents of the digestive 

 tract, including the cerata, resemble hardened jelly, and are probably 

 composed of the eggs of fish, which the animal is said to eat. In this 

 jelly are embedded moderately hard l)lack lumps, detachable from their 

 surroundings and easily friable, which the jelly is not. As mentioned 

 above, in some specimens this black substance forms the major part of 

 the contents of the digestive tract. 



The lobes of the hermaphrodite gland are white, and visible through 

 the dorsal integuments. They are composed of small pouches containing 

 ova, scattered rather irregularly round a larger and more elongate ])ouch 

 containing spermatozoa, and they alternate with the diverticula })roceed- 

 ing from the alimentary canal to the cerata. There is no armature on 

 the penis. The renal organ (PL xii., Fig. 22.) consists of a simple sac 

 with a few constrictions. It does not in my specimens extend as far 

 backwards as indicated by Hecht's figures {Contribution a I'dudc dcs 

 Nudibranches, Mem. Soc. Zool. de France, viii. 1895, pi. iv. figs. 47, 48), 

 but terminates soon after the commencement of the posterior third of 

 the body. 



JANIDiE, BERGTI. 



This family superficially resembles the true Solids, but offers several 

 differences of organization. Except in Madrclla, the radula is niulti- 



* Below the row of denticulations (a) there can be seen under a high power three or 

 four series of niinule pits and projections (b). 



