CHEMNITZIA. 445 



ending at the tentacula, which, though somewhat apart, are 

 united by the usual membrane of the Chemnitzia ; they are 

 thick, broad, short, not very membranous, rounded at the 

 tips, which have the characteristic minute flake- white lobe or 

 inflation. The black eyes are not very near together ; they 

 are immersed exactly and close to the base of each tenta- 

 culum, on minute white circles; they do not in the least 

 invade the area of the neck, but rather impinge on the sta- 

 mens of the tentacula. The effete muzzle or mentum is 

 undoubtedly the continuation of the neck, and has no con- 

 nection with the foot; it is long, slender, grooved at the 

 margins anteally and on each side, the upper and lower surface 

 being perfect and unbroken ; the vertical fissure of the mouth 

 is under the tentacular awning. The foot is of the palest 

 frosted-yellow, exceedingly short, narrow, deeply bifurcated in 

 front, when at rest rounded behind, and a little lengthened in 

 action. The animal examined was an "Alma Venus" and, 

 when fully retracted, occupies the fourth volution ; the light 

 green liver, and very pale red, granular ovarium, occupy the 

 three primary volutions ; but when the animal is fully out 

 in the body of the shell, the liver and ovarium are altogether 

 withdrawn from the first whorls, leaving them perfectly 

 hyaline; they are then deposited in the lower part of the 

 third and the whole of the fourth volution, the other parts of 

 the body and organs being in the fifth and sixth. The narrow 

 arcuated branchial plume of about 15-18 rather coarse, 

 opake, pale drab strands, with the auricle and heart, distin- 

 guished by their intense snow-white colour, are perfectly 

 visible, under a powerful Coddington lens, at the smaller and 

 posterior end of the branchial plume. I have been thus 

 particular as to the site of the organs, because I never met 

 with a shell so perfectly hyaline in which their position 

 could be so well seen. The operculum is an almost invisible 

 film, pear-shaped or suboval, with a narrow border of pale 

 bistre with a pinkish hue ; the striae of increment radiate as 

 in most of the other Chemnitzia ; it is fixed on a plain lobe 

 near the posterior extremity. I saw no ornamental append- 

 ages to the head and neck. In this example the apex is sub- 



