REPORT ON THE SCAPHOPODA. 1 1 



Shell. — Extremely attenuated, very slightly curved, a little flattened laterally, and 

 that chiefly toward the convex curve, so that the form is slightly trigonal, porcellanous, 

 pure white, brilliant. Sculpture : Very flue ; irregular scratches run round the shell, the 

 surface of which is not perfectly uniform ; there are very faint indications of longitudinal 

 texture, and there is in the substance of the shell a certain transverse flocculence. 

 Towards the mouth the shell is extremely thin as usual ; but towards the apex it becomes 

 thick from the smallness of the bore, which lies not in the centre, but nearer the convex 

 curve of the shell. L. T08 in. B. 0'6; at apex 0"04. 



This measurement is taken from the largest of six fragments, none of which preserve the apex 

 of the shell. 



14. Dentalium yokohamense, Watson (PI. II. fig. 1). 



Dentalium yokohamense, Watson, Prelim. Report, pt. 2, Journ. Linn. Soc. Lond., voL xiv. p. 517. 



Station 233. May 17, 1875. Lat. 34° 39' N., long. 135° 14' E. Yokohama, Japan. 

 8 fathoms. Mud. 



Shell. — Much curved when young, becoming nearly straight with later growth, little 

 conical, rather strong, opaque, yellowish white, quite dull, but not chalky. Sculpture : 

 Irregular, slightly elliptical, lines of growth, a little puckered, generally slight, but some- 

 times sharp and even ; towards the mouth faintly imbricated ; occasionally marked by a 

 deep furrow-like constriction of the shell. The longitudinal ribs are eight to nine in 

 number, equal, rounded, rather strong, but not very prominent. These are parted by 

 furrows, round and open, very shallow, and of very unequal breadth. In these furrows, 

 one, two, or even three thread-like riblets appear, and in the whole texture the lens shows 

 a tendency to a longitudinal or rod-like structure. At the apex the shell is squarely 

 truncate, and in the young shell there is, on the convex slope, a slight ragged fissure. 

 L. 1-2 in. B. at mouth 0-15 ; at apex - 003. 



The ribs here are much less sharp than they are in Dentalium dentalis, Linn., and there is no 

 trace of the exquisite longitudinal fretted strias which cover the furrows in that species. The sharp 

 intercostal stria? of Dentalium octogonum are quite absent here ; and in that species, which is much 

 more bent, the ribs are much wider apart and more equally parted. 



15. Dentalium dentalis, Linne. 



Dentalium dentalis, Linne, Syst. Nat., p. 1263, No. 785. 



„ ,, Lamarck, Anim. s. vert., vol. v. p. 34-1, and (ed. Desh.) vol. v. p. 595, sp. 10. 



,, ,, Deshayes, Mem. soc. hist, nat., vol. ii. p. 353, pL xvi. fig. 9, 10, sep. imp., 



p. 33, pi. ii. fig. 9, 10. 

 „ „ Deshayes, Encyclop. method., vers. vol. ii. (part 2), p. 75, sp. 8. 



„ ,, Wood, Ind. Test., p. 191, pi. xxxviii. fig. 5. 



,, „ Hanley, Ipsa Linn. Conch, pp. 436, 548. 



