84 LUCINIDyE. 



subangular laminae, sinuated at the margins, pectinated, and 

 fixed, as is usual, to the dorsal range, the upper plate being 

 little more than half the depth of the lower one. The palpi 

 are short, pointed, pectinated, and subtriangular ; they lie 

 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 intense 

 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 in 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 faecal 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 Lucinae. 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 slight 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 lies 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 



