NUDIBRANCHIATE GASTEROPODA. 



tubercles showing under the magnifying glass, as well as the whole back, fine spicules; the margin 

 of the rhinophore- openings is covered with quite small tubercles, which is also the case with the 

 margin of the round branchial cleft. The strong club of the rhiuophoria appeared to contain 15 — 20 

 pairs of leaves. There were 8 gill-leaves, tripinnate; almost in the middle of the circle the but little 

 conspicuous anal papilla was found. The lower side of the not very broad mantle-edge showed oblique 

 bundles of spicules distinctly to be seen from without. The genital papilla had two openings. The 

 mouth was round, and on each side of it was found the short, truncate tentacle. The foot was anteri- 

 orlv rounded, with a marginal furrow, the foot-brim narrow; the tail rather short, rounded at the end. 



The central nervous system (fig. 17) showed the cerebral and pleural ganglia to be 

 distinctly discerned, almost of the same size, roundish; the pleural ones situated (fig. 17 bb) outside the 

 cerebral ones. The pedal ganglia (fig. 17 cc) were lying behind the former pair, also of a roundish 

 shape, about as large as the cerebral ones, and connected by a rather short commissure. The bulb- 

 shaped proximal olfactory ganglia were almost sessile (fig. 17); the roundish buccal ganglia were 

 connected with each other by a not quite short commissure. 



The black eyes (fig. 17) were quite short-stalked. The otocysts (fig. 17, 18) were lying on 

 the uppermost edge of the pedal ganglia, measured in diameter o-io mm , and contained a rather great 

 number of round and oval, firm otoconia of a diameter of 0-007 — o-oi3 mm (Fig. 18). The leaves of the 

 club of the rhinophore, as well as its axis and the stalk' contained numerous spicules exactly of 

 the same kind as those found everywhere in the skin, especially in large numbers in the back with 

 its tubercles and in the lower side of the mantle-brim. These spicules are long, staff-shaped, cylindrical, 

 or here and there also a little rugged, straight or slightly bent, strongly calcified, clear as glass, and 

 of a diameter of up to o-03' nm ; they are, as is usual with this kind of spicules upon the whole, easily 

 broken, and were often found broken into many pieces. 



The short and powerful bulb us pharyngeus together with the thick, strongly projecting 

 radula-sheath measured in length 2 mm ; the labial disk was covered with a simple, colourless cuticle. 

 The tongue was broad and flat, and appeared to contain 25 rows of teeth, of which the foremost 

 were very incomplete, and the tooth-plates to a great extent broken; farther back in the radula-sheath 

 still 26 rows seemed to be found, of which the hindmost were not yet completely developed; thus the 

 total number of the rows seemed to be 51. The odontogenous cells of the radula-pulp were arranged 

 in long columns forming the long tooth-plates. The number of tooth-plates in the series was con- 

 siderable, but could not be made out. The tooth-plates were completely colourless; the outermost were 

 only o-o8 mm long, while the largest were at least 0'35 mm . The tooth-plates were of the peculiar, before 

 described shape, very long, flattened, and thin, at the point a little broader (measuring 0'0i3 mm ), formed 

 like a spoon, in the point and in part of one edge provided with quite fine and pointed denticles 

 (fig. 19); the outermost tooth-plates were less long and denticulated for a longer way (fig. 20). 



The whitish salivary glands were seen as a small mass on each side of the fore end of 

 the stomach. 



The oesophagus was short; the stomach oblong, of about the same length as the bulbus 

 pharyngeus. 



The anterior genital mass was a little oblong, rather large. The glans penis (fig. 21) pro- 





