38 
THE TOY AGE OF H.M.S. CHALLENGER. 
sacrificed one of each in order to examine the animals. To do this the specimens had to 
be removed from the balsam, and the shell destroyed by acetic acid. 
I was then able to recognise that the so-called Limacinidse were only Gastropod larvae. 
If it be useful to communicate new truths, it is not less necessary to destroy old 
errors. I have for this reason devoted a few sentences to show that the types of Agadina 
(in the sense in which A. and H. Adams use the term) are not really Pteropods. 
# 1. Agadina stimpsoni, A. Adams (PI. I. figs. 11-14). 
1867. Agadina stimpsoni, A. Adams, Description of New Species of Shells from Japan, Proc. 
Zool. Soc. Lond., 1867, p. 309, pi. xix. fig. 23. 
Shell smooth, discoidal, without spire ; three and a half whorls gradually increasing, 
rolled up in the same plane ; rounded oblique aperture, with slightly bell-shaped margins ; 
deep umbilicus, with slightly marked rays. 
Colour. — Yellowish- white. 
Dimensions. — 1 mm. in diameter. 
Operculum. — Horny, circular, externally concave, multispiral, with four and a half 
whorls gradually increasing, left-handed, surface of insertion very large. 
Animal bearing on its head a four-lobed velum ; dorsal pallial aperture ; thick 
columellar muscle ; foot large and strong, bifid in front, with a long broad creeping 
surface, and bearing the operculum at the posterior end ; no fins. 
The small size of this species, and the manipulations which the specimen had to 
undergo (the action of chloroform to remove the balsam, and of acetic acid to dissolve the 
shell), after having been stained and mounted in balsam for twelve years, did not allow 
me to study its structure in any detail. But what has been elucidated is sufficient to 
enable one to decide the group of Molluscs to which this form belongs, and the stage of 
development arrived at. 
Habitat. — Kino Osima (Japan), A. Adams. 
Challenger Specimens. — Living. 
Station 175, August 12, 1874 ; Fiji to Kaine Island ; lat. 19° 2' S., long. 177° 10' E. 
Near Station 206, January 9, 1875 ; China Sea; about lat. 17° 54' N.; long. 117° 14' E. 
Station 216a, February 16, 1875; North of New Guinea; lat. 2° 56' N., long. 
134° 11' E. 
2. Agadina gouldi, A. Adams. 
1867. Agadina gouldi, A. Adams, Description of New Species of Shells from Japan, Proc. 
Zool. Soc. Lond., 1867, p. 309, pi. xix. fig. 22. 
Shell smooth, helicoid, formed of three and a half bulging and rapidly ascending 
whorls ; spire not projecting above the last turn ; oblique aperture with margins slightly 
expanded ; umbilicus very narrow. 
