98 
THE VOYAGE OF H.M.S. CHALLENGER. 
I have already mentioned that I have much doubt in regard to the form of the fin in 
the “ Cymbulia ” from the Indian Ocean, as figured by Macdonald. I am of opinion that 
this species (if distinct from the Mediterranean Cymbulia peroni) belongs to the above 
genus and bears a ventral lobe on the fin. This seems the more likely since Cymbulia 
peroni, in which the ventral lobe is indubitably present, has also been figured by 
Deshayes 1 as if it were really absent. 
Finally, a fourth form of this genus is represented by a specimen without a shell, 
collected by the Challenger in the Pacific Ocean. It is possible that this form corre- 
sponds to Cymbulia parvidentata, n. sp., from New Zealand, of which only the shell 
is known. This cannot, however, be affirmed as fact. The single specimen of the above- 
mentioned form is stained and mounted in balsam ; it is therefore impossible to give any 
satisfactory description. 
The above facts comprise all we know about the Cymbuliidse, from a systematic point 
of view. Abstracting the two forms last mentioned, we may distinguish the other two as 
follows : — 
Key to the Species. 
1. Shell with a somewhat broad cavity, with strong spines, chiefly along 
the aperture, . . . . . . . Cymbulia peroni. 
2. Shell with a very narrow cavity, with small and uniform spines, . . Cymbulia parvidentata. 
1. Cymbulia peroni, de Blainville. 
1818. Cymbulia peronii, de Blainville, Diet. d. Sci. Nat., t. xii. p. 333, pi. lix. fig. a. 
1850. Cymbulia proboscidea, Gray, Catalogue of the Mollusca in the Collection of the British 
Museum, pt. ii., Pteropoda, p. 25 ( non Krohn, 1844). 
This form is sufficiently well known to dispense with a fresh description. I shall 
restrict myself to distinguishing it from the next species. The dorsal portion of the shell 
is swollen and short ; the extremity is markedly obtuse ; the shell does not exhibit any 
constriction at the middle of its length ; the two lines of tubercles, which end in the two 
ventral points, are distinctly parallel, and the spines which bound the aperture are larger 
on the right than on the left. 
Among the numerous figures of this species, many are poor, and few satisfactory. 
That of Boas 2 has been based on a small specimen, preserved in alcohol. The best idea 
of the living animal is obtained from the figure given by Delle Chiaje. 3 
Habitat. — Mediterranean ; Nice, Villefranche, Civita Yecchia, Naples, Messina. 
1 Traits 614mentaire de Conchyliologie, pi. cii. fig. 3. 
2 Spolia atlantica, pi. iv. fig. 30. 
3 Descmione et notomia degli animali eenza vertebre del Regno di Napoli, pi. xxxii. fig. 1. 
