80 
THE VOYAGE OF H.M.S. CHALLENGER. 
The following is a list of the species : — 
1. Ceratosoma cornigerum (Adams), Bergh. 
Indian Ocean, Philippine Sea. 
2. Ceratosoma gracillimum, Semper. 
Philippine Sea. 
3. Ceratosoma trilobatum, Gray. 
Red Sea. 
4. Ceratosoma polyomma, Bergh. 
Pacific Ocean (Pelew Islands). 
5. Ceratosoma caledonicum, Fischer. 
Pacific (New Caledonia). 
6. Ceratosoma brevicaudatum, Abraham. 
Pacific. 
7. Ceratosoma oblongum, Abraham. 
Pacific (West Australia). 
8. Ceratosoma tenue, Abraham. 
Habitat ? 
Ceratosoma cornigerum (Adams), Bergh, var. ? (PI. II. figs. 14-17; PL III. figs. 14-20). 
Ceratosoma cornigerum, A. Adams, Voyage of tlie “Samarang,” Mollusca, 1848, p. 68, pi xix. fig. 5. 
„ Adams, Bergh, Malacolog. Untersuch, loc. cit., Heft x., 1876, pp.393-403, 
Taf. xlviii. figs. 15-27, Taf. xlix. figs. 1-5. 
Habitat. — Philippine Sea (Samboangan). 
One specimen of this species was dredged at Samboangan, in company with Platydoris 
eurychlamys and Discodoris morphcea, on February 1, 1875, from a depth of 10 fathoms. 
The specimen was well preserved in alcohol, and measured 4 '3 cm. in length by 1 in breadth 
and 1 • 5 cm. in height ; the hinder dorsal process, moreover, measured 6 mm. ; the breadth 
of the foot 5 mm., the length of the tail 16 mm., the height of the rhinophoria 3 mm., of 
the branchia 3'5 mm. The colour was greyish-red, white speckled and covered with numer- 
ous white dots, especially on the anterior portion of the back. The stem of the rhinophoria 
