156 SERPULA. CREEPER. 
Shell glossy white, opake, rather flat, oblong-oval* with 
three compartments ; on one edge is a single longitudinal 
suture apparently dividing it into two parts; on the other 
side a faint depression investing the middle compartment 
which is more raised, and separating it from the outer- 
ones : aperture produced into a very short neck, oval and 
edged with yellow * length not half a line. 
In fine sand: very rare. v. in. 
19. Serpula hi cor m3. Two-horned Creeper. 
Walker, f. 2. 
• Shell glossy white, opake, flattisli, somewhat oval, 
smooth on the* upper side, striate longitudinally from the 
aperture on the other : aperture contracted, small, orbicu¬ 
lar : length a line. 
Variety. Perforated in the centre. 
Walker, f. 3. 
In fine sand : very rave. v. m. 
20. Serpula incurvata. Curved Creeper. 
Walker, f. 11. 
Shell white, semitransparent, smooth, cylindrical, 
straight, but curved at the smaller end into three close vo¬ 
lutions or compartments : length hardly a line. It resem¬ 
bles the Nautilus semilituus, but is perfectly smooth and 
cylindrical, and has neither syphon in the aperture, nor in¬ 
ternal cells nor joints. 
Variety. With a single volution at the end, and pervious. 
Walker, f. 12. 
In fine sand : very rare. v. m. 
The three first species of this subdivision are evidently 
distinct from each other in the form of the aperture, which 
never interchangeably varies, although Mr. Dillwyn has 
united them ; the fourth lie has omitted altogether. 
D. Detached, and bottle-shaped, 21 to 20, 
21. Serpula lactca. Egg Creeper. 
Walker , f. 5. 
Shell thin, transparent, egg-shaped but a little flattened, 
with generally four milky lines .separating the compart¬ 
ments, 
