558 PROF. C. H. o'DONOGHUE : REPORT ON 
have been wholly brown." This agrees closely with my own observations, 
and the peeling o£ the epidermis is also similar. The radula formula is 
given as 60 . . 60, and the total number of rows 23 ; this is not quite the 
same, but the teeth are apparently identical. He says, further, " oral 
tentacles white ; large, flat, and distinctly grooved." This is not at all in 
agreement with the present specimens^ and, indeed, is not found in other 
members of the genus. Eliot's form from its teeth and other features 
undoubtedly is referable to this genus, and I am inclined to think that this 
description of the tentacles is not quite accurate. 
In spite of this one serious discrepancy, the present forms agree so closely 
with the description of A. affinis given by Eliot, that I think it safer to refer 
them to that species than give them a new specific name. 
Grenus Cbratosoma Adams & Reeve, Voj^ageof ' Samarang,' 1848, p. 67. 
Type by monotypy : C. cornigerium, Adams & Reeve, idem, p. 68. 
Species Ceratosoma brevicaudatum Abraham, Ann. & Mag. Nat. Hist. (4) 
xviii. p. 142, pi. 8. fig. 6 (1876). (PI. 28. fig. 14; PI. 30. 
figs. 57-59.) 
Synouym: C. oblonc/mi Abraham, I.e. p. 143, pL 7. figs. 7, 7 a, 7b. 
Bergh (25) suggests that C. caledonicum Eischer, C. tenue Abraham, 
and C. oblongum Abraham are all synonyms of C. brevicaudatum Abraham. 
Basedo'w and Hedley (8, p. 154) call attention to the following :— in the case 
of C caledonicum, Fischer's description indicates an animal with the lobes of 
the notseum more developed, and the colour-scheme in the two forms is 
entirely different. This being so, it seems undesirable to merge the two into 
one species without further evidence. The same two authors suggest that the 
differences between C. brevicaudatum and C. oblongum are due to the amount 
of contraction undergone upon or before preservation, and state that they 
have obtained examples of this species exhibiting similar differences from the 
same dredging. An examination of the external characters of the original 
specimens described by Abraham, and preserved in the British Museum, leads 
me to think that they are probably right, and that C. oblongum is to be 
regarded as synonym of C. brevicaudatum. I have also examined the original 
examjDle of C. tenue described by Abraham, and, while it is possible that it 
may also be a synonym, it is somewhat different in appearance, and it is 
probably better — for the present, at any rate — to keep it separate, as has been 
done by Basedow and Hedley. 
The specimens here described agree closely with the original description 
given by Abraham and that furnished by Basedow and Hedley, and are 
undoubtedly referable to C. brevicaudatum. 
Body. The body is large, elongated, slightly wider in the middle than at 
the two ends, and it increases in height from before backwards to the middle 
or just beyond. The sides are high, almost vertical, and practically parallel. 
The back is flattened and continued out into a narrow undulating mantle- 
