yOL. LXXV.] PHILOSOPHICAL TRANSACTIONS. 3 



their origin from the body of the animal, and make 5^ spiral turns round each, 

 being lost in the points of the cones ; they are loose from the cone at the lowest 

 spiral turn which they make, and are nearly half an inch in breadth ; they are 

 exceedingly delicate, and have at small distances fibres running across them from 

 their attachment at the stem to the loose edge, which gives them a ribbed ap- 

 pearance. These fibres are continued about -^ of an inch beyond the mem- 

 brane, having their edges finely serrated, like the tentacula of the Actiniae found 

 in Barbadoes : these tentacula shorten as the spiral turns become smaller, and 

 are entirely lost in that part of the membrane which terminates in the point of 

 the cone. 



Behind the origin of these cones arises a small shell, which, for -^ of an inch 

 from its attachment to the animal, is very slender : it is about -f- of an inch in 

 length, becoming considerably broader at the other end, which is flat, and about 

 4- of an inch broad ; the flattened extremity is covered with a kind of hair, and 

 has rising out of it 2 small claws, about -^ of an inch in length. If the hair, 

 and mucus entangled in it, be taken away, this extremity of the shell becomes 

 concave, is of a pink colour, and the 2 claws rising out from its middle part 

 have each 3 short branches, not unlike the horns of a deer. The body of this 

 shell has a soft cartilaginous covering, with an irregular but polished surface : on 

 this the cones rest in their collapsed state, in which state the whole of the shell 

 is drawn into the cavity of the brain-stone, excepting the flattened end with the 

 2 claws. Before the cones there is a thin membrane, which appears to be of the 

 same length with the shell just described. In the collapsed state it lies between 

 the cones and the shell in which the animal is inclosed ; but, when the tentacula 

 are thrown out, it is also protruded. 



The shell of this animal is a very thin tube, adapted to its body : the internal 

 surface is smooth, and of a pinkish white colour ; its outer surface is covered by 

 the brain-stone in which it is inclosed, and the turnings and windings which it 

 makes are very numerous. The end of the shell, which opens externally, rises 

 above the surface of the stone on one side half an inch in height, for about half 

 the circumference of the aperture, bending a little forwards over it, and becom- 

 ing narrower and narrower as it goes up, terminating at last in a point just over 

 the centre of the opening of the shell ; on the other side it forms a round 

 margin to the surface of the brain-stone. This part of the shell is much 

 thicker and stronger than that part which is inclosed in the brain-stone : its 

 outer surface is of a darkish brown colour; its inner of a pinkish white» The 

 animal, when at rest, is wholly concealed in its shell ; but when it seeks for 

 food, the moveable shell is pushed slowly out with the cones and their mem- 

 branes in a collapsed state ; and when the whole is exposed, the moveable shell 

 falls a little back, and the membrane round each of the cones is expanded, the 



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