REPOET ON THE NUDIBRANCHIATA. 
143 
cruise of the Danish vessel “ Galathea” in 1846, and was taken in Pulu-Milu, one of the 
Nicobar Islands, on the 7th November, on the shore. It belongs to the collection of the 
museum at Copenhagen, and was handed over to me for study by Prof. Steenstrup. 
The specific name was verified by Semper, who investigated all the specimens of 
Onchidium in the museum. It was well preserved in alcohol, but rather contracted. 
Its length is 7 '5 cm., breadth 5 '8 cm., height 3 cm. ; the breadth of the mantle edge is 
18 mm., of the foot 28 mm., and of the frontal shield 20 mm. ; the edge of the foot projects 
4 mm. in front; the length of the tail is 2 ‘5 mm. ; the length of the rhinophoria 4 '5 
mm. ; the diameter of the pneumostome 2 mm. ; the anal papilla is 1 ’4 mm. in length ; 
the breadth of the aperture of the penis, which lies a little to the right, is 2 mm. 
The position of the viscera was quite as in the last species. The pseudo-peritoneum 
was colourless, but greyish-black beneath and at the sides. 
The centred nervous system, the rhinophoria, and the eyes resemble those of the last 
species. I did not find the otocyst. Semper has accurately described the dorsal eyes ; l 
in the specimen examined by me there appeared to be only a small number of groups 
of eyes, and a small number of eyes in the groups. 
The buccal tube was about 9 mm. long by 9 ‘5 mm. in breadth. The bidbus pharyngeus 
as above, but the upper side more gradually arched ; its length was 1 1 mm. , height 
10 '5 mm., and breadth 10 mm. ; the radula-sheath, moreover, projected behind 4 mm. 
I found the usual palatal plates, which were longer, narrower, paler coloured and less 
conspicuous ; in structure hardly different, save that the denticles were mainly 
conical and longer (about ‘28 mm. long). The tongue presented no differences ; in 
the chestnut-brown coloured radula there were forty -three series of teeth ; further back 
forty-two, of which the four hindermost were not fully developed ; the total number 
was thus eighty-five. The eight anterior series were much worn, even their median 
teeth, and also the following series, but in a less degree. In the hindermost rows of the 
tongue there were 106 teeth (on either side), further back the number did not increase to 
more than 108. The shape of the teeth was hardly different from that of the last species. 
The salivary glands were also similar ; the left gland 1 2 mm. long, 8 mm. broad, and 
2 '5 mm. thick, somewhat bent, and traversed by furrows on both sides; otherwise fairly 
smooth, the margin lobate. The right gland is a little shorter and thicker, and rather 
more lobate. 
The oesophagus resembles that of the previously described species ; its length is 
3 cm., and the diameter 3 mm. anteriorly and 1'5 mm. posteriorly. The first stomach is 
irregularly spherical, about 8 mm. long by 8*5 mm. in diameter; inner surface like that of 
the previously described species. The second, masticatory stomach, is 12 mm. long, 
16 mm. broad, and 11 mm. in thickness; its form and the tendinous patches are like 
1 Loc. cit., Lanclmollusken, Erganzungsheft, 1877, p. 4, Taf. A. fig. 2 ; Taf. B. figs. 3, 4 ; Taf. C. fig. 9. — Heft 
v. 1880, p. 258. 
