52 CLASS GASTEROPODA. 
To these two, now well known genera, I presume we must 
add, when better known, 
TIMORIENNA, Quoy et Gaim., Zool. de Freyc. pl. Ixxx. f. 
1, which appear to be firole deprived of their foot and bundle 
of viscera. 
And the 
MonoPHorRa, id. ib. f. iv. and v., which has nearly the 
form of a carinaria, but is without a foot, distinct bundle of 
viscera, and shell. 
We must not confound them with the monophore of M. 
Bory St. Vincent (Voy. aux Isles d’Afr.), which are pyrosome. 
It is not certain that we should place here 
PHYLLIROE, Péron, Ann. du Mus. XV. pl. ii. f.1., where the 
transparent and strongly compressed body has a snout before, 
surmounted by two long tentacula without eyes, a truncated 
tail behind, and which allows its heart, nervous system, 
stomach, and the genital organs of both sexes, to be seen 
through the integuments. The genital orifices and the anus 
are on the right side, and sometimes a tolerably long penis is 
visible. I can find no other organ of respiration than its thin 
and vascular skin. 
THE SIXTH ORDER OF GASTEROPODA. 
THE PECTINIBRANCHIATA 
Form, beyond all comparison, the most numerous division, 
inasmuch as they include the whole of the spiral univalves, 
