ON DREDGING AMONG THE SHETLAND ISLES. 433 



Siphonodentalium, the mouth is coutracted or pinched-in, and the auimal 

 is annulose and has a circular opercnlnm. On the other hand, several kinds 

 of shelly cases described as Dentalia really belong to Ditri/jia. If Cadulus 

 is not generically distinct from SijiliotiodentaVnun, the former of these names 

 has priority ; and we shall thus be able to expunge a more than sesquipe- 

 dalian name fi'om the terminology of the MoUusca. The diagram now exhi- 

 bited is an enlarged representation of the figures of S. Lofotense and S. siib- 

 fiisiformis,fvovi an admirable paper by Professor Sars, published in the Transac- 

 tions of the Academy of Sciences at Christiauia for 1S64 ; and it wiU serve to 

 explain the nature of these extraordinary mollusks. One of our species is 



^ijplionodentalkmi Lofotense, Sars 



(" Malacozoologische Jagttagelser," in Vid.-Selsk. Porh. 1864, p. 17, figs. 

 29-33), ranging from the Loffoden Isles to Christianiafiord, at depths of be- 

 tween 30 and 120 fathoms. It was rather plentiful among sandy mud in St. 

 Magnus Bay, at the depth of from 60 to 80 fathoms ; and I had found it in 

 1846 when dredging off Skye, in 1864 off' Unst, and last year in the Minch. 

 The shell may easily be passed over — as it was by me — for the young of Denta- 

 liam entalig ; but it is more curved and cylindrical, the mouth and correspon- 

 ding lines of growth slope backwards, and the margin of the posterior orifice 

 is regularly jagged (having two slight notches on each side), and this extremity 

 does not form a bulbous point in the frj^ One of the characters given by Sars 

 ("margine aperturse posterioi'is integro ") should be amended. My observa- 

 tion of the animal agreed with his, except that the foot is vermiform and has a 

 fine point, the disk being expanded and assuming the shape of a flower only 

 when the Siphonodentalium wishes to obtain a fulcrum and keep its place in 

 the sand. The foot of Niicida and Leda is somewhat similar, its disk when ex- 

 panded resembling the leaf of a palm. Another species oi Siphonodentalium pro- 

 per is Dentalium quinquanyidare of Forbes, from the ^gean (80-230 fathoms), 

 which M'Audrew afterwards dredged off the coasts of Portugal and Spain in 

 5-30 fathoms, and named (lapsii calami) D. 5"af?'"«'i^M^«''^; this species Sars 

 lately procured from the Loffoden Isles and Christianiafiord in 50-300 fathoms, 

 and described as S.pentacjonum. The coincidence of the first and last of these 

 specific names is curious. Z>. ^/crt/'(7i«<H«i of Deshayes (a tertiary fossil) may 

 also be referable to the genus Siphonodentalium. D. hijissum of Searles Wood, 

 from the Coralline Crag, is possibly the type of another genus, for which I 

 would suggest the name of Dischides. This species has been dredged in a 

 living state off Gibraltar by Mr. M'Audrew *. I suspected that D. hijissum 

 might be the tube of a young Teredo norvegica, on account of its having a 

 septal jjrocess within the posterior orifice : at all events my remark is justi- 

 fied by the affinity which exists between the Teredinidce and the Soleno- 

 conchia. 



The second species of this class is 



Cadulus suhfusiformis, Sars 



{Siphonodentalium subfusiforme, 1. c. p. 21, figs. 36-44), having a Korwegian 

 distribution equally extensive with that of S. Lofotense, but attaining a greater 

 deptli, viz. from 50 to 300 fathoms. I noticed specimens among the fossils 

 collected last year by Messrs. Crosskey and Eobertson in a raised sea-bed at 

 Barholmen, near Christiania. It occiirred on the Unst ground, in 80-90 

 fathoms, and was apparently not rare. Mr. Peach detected a specimen in 

 looking over some sand which I dredged there in 1864 ; this I at the time 



* It inhabits also the European and African coasts of the Mediterranean. 

 1867. 2 G 



