2 8 NUDIBRANCHIATE GASTEROPODA. 



divisions were strongly marked off from each other, almost globular; the cerebral ones were a little 

 larger than the pleural ones. The pedal ganglia proceeding downward and inward from the mass of 

 the cerebro-pleural ganglia, were of a short-ovate form, a little larger than the cerebral ones, connected 

 by a double commissure, which was shorter than the diameter of the ganglia. The buccal and gastro- 

 oesophagal ganglia as in the typical species. 



The eves of a diameter of o-n mm , with a black pigment, and dark yellow lens of a diameter 

 of o'03 mm . 



The bulb u s p h a r y n gens was 6 mm long, by a breadth of 5"5 mm , and a height before of 4 mm , 

 behind of 3 mm ; its form was as in the typical species. On each side of the round labial disk was seen 

 inwardly a narrow, irregular, dirtily yellow stripe, which was formed of straight or irregularly bent, 

 onlv little stiff, unequally long, unequally thick, colourless or slightly dirtily yellowish staves (fig. 3) 

 of a length of at least o - i6 mm by a breadth of o-ooj 1 "" 11 ). The mandibles were about as long and 

 high as the bulbus pharyugeus, lemon-coloured, only in the hinge-part of a black-brown colour. The 

 projecting portion in front and above together with its prolongation as in the typical species; the 

 masticatory process short with a not large number (at most ca. 50) of denticles which only reached to 

 a height of 0'04' nn ' , and were rather worn and blunt. The secondary (supplementary) oral cavities 

 were rather large, and their opening not narrow. The tongue as usual short, powerful, and keelshaped, 

 with a long foremost, and short upper edge (fig. 28). in the radula, which on account of the median 

 teeth is yellow, were counted on the fore edge of the tongue n series of tooth-plates, and marks 

 after several that had fallen off, and on the short upper edge three series; the continuation of the 

 radula in its sheath in the greatest length light red, and containing 16 series of tooth-plates, of which 

 the two hindmost ones were not yet developed; the total number of series was thus 30. The fore- 

 most series were very incomplete, and most of the teeth on the tongue w T ere much worn. The breadth 

 of the oldest median teeth was o p i8 mm , in the hinder part of the tongue it rose to o-22 mm , and upon 

 the whole it rose to o-29 m '". The strongly coloured median tooth-plates had a strongly projecting 

 hook, on this and to both sides of it was found a not very large number (most frequently about 25) 

 of not very strong denticles (fig. 4). The number of the almost colourless lateral tooth-plates varied 

 from 13 to 15; the innermost plate was a little smaller than the following one, they decreased in size 

 outward, and the two outermost ones, especially the very outermost one, were small; none of them 

 showed (through the whole length of the radula) any trace of denticulation (fig. 5) 2 J. 



The salivary glands were as in the typical species. 



The oesophagus in the first (3"™ long) part is rather narrow, then widening and with 

 numerous longitudinal folds that shine through on the exterior, running on and between the two 

 anterior livers, altogether about 14""" long. The thinwalled stomach, which is also provided with 

 numerous longitudinal folds, is almost globular, of a diameter of 5 mra , and situated before the principal 



'I In the two specimens of D.robustus that I have examined earlier, no traces of such a prehensile ring were 

 seen, and only in 4 out of 12 examined individuals of D.arborescens; in a specimen of Dendr. Dalit trie prehensile ring was 

 not wanting, nor in a single specimen of D. purpureas. 



1 Verrill as well as G. O. Sars state the lateral teeth also to he quite or almost quite without denticulation; on the 

 contrary the specimen earlier examined by me, showed a slight and irregular denticulation. The denticulation of the lateral 

 teeth in the Dendronotidae is upon the whole always much varying. 





