REPORT OX THE SCAPHOPODA. 15 



The specimens are young, and both ends are chipped. 



It is straighter and more tumid than Siphodentalium minutum, H. Ad. (Gulf of Suez, MacAndrew), 

 and not contracted at the mouth. It is also straighter and more tumid than Dentalium filum, Sow. 

 (in part), = Dentalium gracile, Jeffr., Journ. de Conch., 1872, p. 140, pi. v. fig. 5, but more curved 

 and broader than the young of Dentalium capillosum, Jeffr. It is much larger, more tumid, and 

 straighter for the same length than Siphodentalium lofotcnse, Sars. 



4. Siphodentalium dichelum, 1 Watson (PI. II. fig. 7). 



Siphodentalium dichelum, Watson, Prelim. Report, pt. 2, Journ. Linn. Soc. Lond., vol. xiv. p. 521. 



July 29, 1874. Levuka, Fiji. 12 fathoms. 



Shell. — Long, slightly swollen at about three-fifths of its length ; the swelling bulges on 

 the concave curve, but the convex curve is uninterrupted; between these. two curves it is 

 compressed by one-sixth of its breadth, a little contracted in front, bent and attenuated 

 toward the apex ; thin, brilliant white, almost hyaline, with a few minute, transverse, curdy 

 streaks, but weathering to opaque. There is an opaque band round the apex. Sculpture : 

 Most faint and delicate microscopic scratches on the lines of growth, with a minute 

 transverse flocculence and some vague indication of longitudinal texture in the substance 

 of the shell. The mouth is large, very oblique, with a smoothly rounded edge, which is 

 sharp on the inner margin ; both it and the posterior opening are oval. The apex, which 

 is small, is split on either side by a deep, narrow, slightly widening, smooth, clean-cut, 

 but not perfectly regular cleft, which is evidently carried down the shell as the growth of 

 the animal demands, for it cuts across the transverse striae, as Mr Searles Wood remarks 

 is the case with Siphodentalium (Dischides) bifissum. Within the opening a short, 

 minute, longitudinal, rib-like process projects along the middle of the posterior (i.e., 

 convex curve) wall ; a little farther in, a thin, narrow, circular callus runs round the open- 

 ing. L. 0.35 in. B. at mouth 0"032; broadest 0^055 ; apex 0"022. 



This is much larger than Siphodentalium tetraschistum, Wats., and much less cylindrical, being 

 much more contracted towards the mouth. The posterior internal rib is a curious feature. It shows 

 through the shell like a crack or depression, but is a true internal rib. 



5. Siphodentalium tetraschistum,' Watson (PI. II. fig. 8). 



Siphodentalium tetraschistum, Watson, Prelim. Report, pt. 2, Journ. Linn. Soc. Lond., vol. xiv. p. 521. 



Station 113a. September 1, 1873. Lat. 3° 47' S., long. 32° 24' 30" W. Anchorage 

 off Fernando Noronha. 25 fathoms. Volcanic sand and gravel. 



Shell. — Cylindrical, tapering, bent and attenuated from about the middle to the apex ; 

 toward the mouth very slightly contracted. It is rather strong, and has the dull gloss 



1 bly^ko;, cloven. 2 TiTsda^srof, split into four. 



