84 LUCINIDA. 
subangular lamin, smuated at the margins, pectinated, and 
fixed, as is usual, to the dorsal range, the upper plate bemg 
little more than half the depth of the lower one. The palpi 
are short, pomted, pectinated, and subtriangular; they he 
on each other, and I may say, that neither of these organs 
present any remarkable variation from the usual run of the 
Acephala. The liver on the dorsal range is of an imtense 
black-brown granular substance, with the ovary mixed up with 
it, more anteriorly. There are no siphons, but only a short 
pendulous rectum, which is a very minute cylinder, discharging 
by what I considered to be a crenulated slit m the mantle 
high up in the posterior dorsal range. If I am mistaken as 
to the slit, which possibly may have been an accidental lesion, 
in that case it would discharge within the walls of the mantle, 
and finally eject from the central pedal aperture, which is a 
large opening commencing from the posterior closure of the 
mantle to the anterior adductor muscle, situated very low, near 
the anterior ventral range, from whence the mantle becomes 
closed to the anterior dorsal range; therefore there are only 
two apertures in the mantle, the small posterior slit, for the 
ejection of the excessively minute fecal pellets, and the very 
large ventral opening for the foot. The possession, as yet, of 
only one good-sized specimen has not enabled me to speak 
positively as to the existence of the anal fissure, but beyond 
doubt there is neither anal nor branchial siphon. 
The foot is a most curious organ; it is characteristic of 
the typical Lucine. It proceeds from the centre of the body, 
and represents a long, lax, flat, rugose, annulated, retractile 
hose, with a wrinkled, elastic, clavate continuation or off- 
spring, with shght shoulders to the terminus, which appears 
to be perforated; this latter, somewhat club-shaped portion, 
when in quietude, folds on the penultimate part, and the 
whole hes within the mantle. It is difficult to conceive how 
a flat, lax, strap-shaped, tubular pedal appendage should in 
action suddenly assume the appearance of an elongated, arcu- 
ated, pointed conical foot, as is represented in the figure of 
the ‘British Mollusca,’ which, however, cannot be improved 
as to actual appearance when the foot is exserted, except 
