155 
above, of a light bluish black mingled with flesh-colour, striated upon 
the surface and upon the anterior side, divided by a broad and shal- 
low canal, ending in a deep and wide anterior notch, which is cut 
square at the base. The canal and notch are bounded on the right 
by a smooth, linear, flesh-coloured rib, which is a little prolonged 
and truncated at the end with a furrow throughout its length. ‘The 
left side of its inferior surface is striated above, sinuous at the margin 
and finely denticulated at its base, which is of a rosy red. 
2. Navicetza variaBiuis. N. testd ellipticd, striis via sub lente can- 
cellatd, lineolis transversis undulatis obsoletisque sepits confluen- 
tibus olivaceis et maculis lutescentibus nigrescente antic obumbratis 
variegatd ; apice marginali eroso, retusissimo ; labio albo, postice 
aurantio, margine subrecto ; aperturd albido-cerulescente. 
Long. 1:16 ad 1:28; lat. 0°80 ad 0°84; conv. 0°46 ad 0°54 poll. 
Var. 5. T. ovatd, postice subtruncatd, tenuiusculd ; apice ante mar- 
ginem inserto, deroso. 
Long. 1:24 ad 1:28; lat. 1°10 ad 1°14; conv. 0°52 ad 0°56 poll. 
Hab, Cagayan, province of Misamis, island of Mindanao: found 
on stones in a large river. 
Although these two varieties appear to differ from each other in 
the position of the summit, I do not think they can be separated. 
Nevertheless the operculum varies perceptibly, and if their respective 
characters proved constant, which it would be necessary to verity by 
examining a certain number of specimens, then alone could one be 
distinguished from the other. The surface of this Navicella shows 
upon the anterior side longitudinal strie, as deeply impressed as the 
tramsverse ones. 
The operculum of the type is blackish throughout, except at, the 
base, which is of an orange-red. The anterior side is notched. The 
dental apophysis is linear, smooth, a little raised, faintly striated both 
longitudinally and transversely. The external margin of this tooth 
projects but little, and its inferior part shows the commencement of 
a crest, but without teeth. 
The operculum of the variety is of a rosy colour, with the inferior 
margin of an orange-red; the anterior side is more slightly notched 
in the middle, its dental apophysis projects rather more, and is linear, 
smooth, and divided by a longitudinal groove. The external margin 
of this tooth is narrow, without any trace of a denticulated crest at 
its base. 
8. NAVICELLA suBoRBicuLARIS. Sowerby, Cat.Tank. App. p. 10. 
No. 1092; Récluz in Guérin, Rev. Cuv. 1841. p. 377. No. 10. 
Var. 3. Récluz, l.c.; Rumph. Mus. Amb. p. 40. f. 0. Optime. 
Var. y. Minori, tenuiori. 
Hab. ad Insulas Philippinas. From the island of Camiguing : found 
on stones in mountain-streams. Var. (, from Cagayan, province of 
Misamis, island of Mindanao: on stones in a large river.- Var. y, 
from Banguey, province of North Ylocos, island of Lugon: found on 
stones in a small stream. 
I see neither in the general form nor in the operculum of these 
