100 
THE VOYAGE OF H.M.S. CHALLENGER. 
Cymbuliopsis , 1 n. gen. 
Characters and Description. — “ Shell ” in form of a slipper, with thin walls, and 
a very large cavity extending to the dorsal extremity. The latter is rounded, while the 
ventral extremity, which is very delicate, ends in a level margin. The whole external 
surface is covered with small, uniform tubercles ; the 
aperture is of considerable size ; its margins do not bear 
spines. 
The animal has a fin without ventral lobe, that is 
to say, with a continuous ventral margin. The proboscis 
Fig. 2.— Sagittal section of the shell of *' _ ° r 
Cymbuliopsis, in which the dotted line i s f ree throughout its entire length, but is short and broad. 
indicates the aperture. 0 
No radula or jaws. 
Two species described as Cymbulia ought to be referred to this genus — Cymbulia 
ovata, Quoy and Gaimard, and Cymbulia calceola, Terrill, 
Key to the Species. 
1. Shell somewhat constricted at the two ends, aperture shorter than the half- 
length of the shell, ........ Cymbuliopsis ovata. 
2. Shell rather broad at the two ends, aperture longer than the half-length of the 
shell, ......... Cymbuliopsis calceola. 
1. Cymbuliopsis ovata (Quoy and Gaimard) (PL II. figs. 15, 16). 
1832. Cymbulia ovata, Quoy et Gaimard, Voyage de decouvertes de l’Astrolabe, Zoologie, t. ii. 
p. 373, pi. xxvii. figs. 25-30. 
1852. Cymbulia ovularis, Rang, Histoire naturelle des Mollusques Pt4ropodes, pi. xi. figs. 1-6. 
Characters and Description. — Shell ovoid, very broad in the middle region, 
constricted towards the ends, and especially at the ventral extremity, where it is very 
little thickened. The external surface is covered with small uniform tubercles, regularly 
distributed, but somewhat distant. The aperture is very nearly as long as the half- 
length of the shell. 
The animal exhibits all the characters of the genus. The proboscis is somewhat 
broad towards the extremity. Quoy and Gaimard have mistaken the proboscis for the 
ventral lobe of the fin of Cymbulia. The fins which they note as being separated by a 
hollow, have a continuous margin like Cymbuliopsis calceola and Gleba. 
Dimensions. — The shell measures from 2 to 3 cm. in length. 
Habitat. — Amboina (Quoy and Gaimard). The British Museum collection includes 
several specimens, but without note of locality. 
1 Cymbulia, and &pif, appearance. 
