DREDGING ON THE COASTS OF SHETLAND. 331 



Siiout broad, bilobed in front. 



Eyes none. 



Foot oval, cloven in front, -with a large triangular expansion or ear-shaped 



process at each side of this part, widely, deeply, and evenly forked 



behind. 

 Ovary yellowish brown. 

 Shell barrel-shaped, but much narrower at the top than the bottom (where 



it is considerably expanded), thin, nearly transparent, and shghtly 



prismatic. 

 Sculpture apparently smooth, but exhibiting under the microscope a few 



slight and indistinct spiral stria3. 

 Colour white, except the apex or nucleus, which is hom-colour. 

 Spire truncated. 



Suture deep or channelled, and somewhat angulated. 

 Whorls three and a half, rapidly increasing ; the first is nipple -shaped, and 



projects beyond the rest. 

 Mouth pear-shaped, upper comer not quite reaching to the spire j base 



spread out and rounded. 

 Outer Up thin and flexuous. 



Pillar-lip folded outwards, at first straightish, and afterwards curved. 

 Umhilicus narrow and groove-Hkc, formed by the reflexion of the pUlar-lip. 

 Length, -215 ;. breadth, -ISo. 



Habitat. Shetland, in muddy sand, 82 fathoms, fifty miles S.S.E. of the 

 Whalsey Skerries ; and on a sandy bottom called the " Haddock groimd," 

 43 fathoms, at a distance of about five miles from the shore between the 

 Skerries and Fetlar Island. One living specimc a was dredged in each of 

 the",e peaces, and a dead shell also in the former; it appears, therefore, to be 

 a rare species. The animal is bold and active, and crawls rapidly. It diifers 

 from that of A. hyaVina in colour ; in the front lobes forming part of the foot 

 in the present species, but of the srout or head-veU in the other (which 

 in that species resemble tentacles, and are folded back or carried erect 

 when the animal crawls, as in Cylklma) ; in the total want of eyes ; and in 

 the taU of the foot being evenly forked Lu A. expansa, ."ud unequally divided 

 or heterocercal in A. liyalina. The absence of eyes is a remarkaWe character ; 

 and there can be no question of the fact, so far as the best optical instruments, 

 long and patient examination under the most favourable circumstances, and 

 the concurrent testimony of three practised observers can establish it. A 

 living individual of each species was placed side by side, and fuUy displayed 

 itself. One had distinct eyes, wnich were vsddely separated, placed outside 

 the shell, but far back on the head-veil. The other, which was three times 

 as large and equally exposed to view, exhibited no trace of eyes anywhere, 

 although it was examined in every position in order to detect their existence. 

 They could not have been subcutaneous, because the tissues of the animal 

 were nearly transparent, and a high microscopical power was employed, by 

 which the internal structiu'e was clearly seen. Analogous cases occur in 

 Eulima distorta and E. stenostoma, as well as in Mangclia nebula and M. 

 nivalis among our native -moUusks. The shell of A. expansa diifers from 

 that of A. liyalina chiefly in being broader and more dUateu at the sides ; it 

 is likewise of a mucn larger size. From A. glohosa it may be distinguished 

 by its greater solidity, being proportionally larger, and especially in the form 

 of the spire, which is broader and entirely visible, instead of being (as in the 

 last-named species) acuminated or erding in an obliquely angular point, so 



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