154 
ON THE DEVELOPMENT OE CIERIPEDIA. 
indicated by dots, as coming out well only when a higher power is used. 
Natural size : — 
Length of pedunculus LO millim. 
Length of upper portion 3-0 millims. 
Total length 4‘0 „ 
Height of ta l . 04 millim. 
Length of ta 2 0‘3 „ 
Fig. 27. The antenna of the Cypris stage. 1, 2, 3, 4, the four joints; aeet, the sucker; 
sp, spine at the base of the joint which is attached to the body ; dgl, duct of 
the gland; m, muscles; set, setae; cs, olfactory hairs; u, flat, doubtful 
appendage, enlarged in fig. 27, u. 
Fig. 28. First formation of the ovary in the Cypris stage, got by dissecting the animal 
when alive. 
Fig. 29. First maxilla of the adult Lepas. 
Fig. 30. The mandibles of an adult Lepas. a, the right mandible, with five teeth ; 
5, the left mandible, with six teeth. 
Fig. 31. Half of the labium (second maxilla) of an adult Lepas. H. 
Fig. 32. The organs of the mouth, as seen in situ in a dissected Cypris. As I did not 
succeed in separating them well, they may not have come out quite accu- 
rately. High power, a, mandible ; b, first maxilla ; c, second maxilla. 
[Note. — The author of this paper, a young naturalist of the highest promise, died on 
board the ‘ Challenger ’ on the voyage from the Hawaiian Islands to Tahiti. In correcting 
this his last scientific paper for the press I have made as few changes as possible, only 
altering the arrangement here and there to make the English run more smoothly ; and, 
in memory of his industry and enthusiasm, I have allowed several passages to stand 
referring to his hopeful anticipations for the future. — C. Wyville Thomson.] 
