among the Shetland Isles. 251 
and Leda is somewhat similar, its disk when expanded resem- 
bling the leaf of a palm. Another species of Siphonodentalium 
proper is Dentalium quinquangulare of Forbes, from the Aigean 
(80-230 fathoms), which M‘Andrew afterwards dredged off the 
coasts of Portugal and Spain in 5-30 fathoms, and named 
(lapsu calami) D. guadrangulare ; this species Sars lately procured 
from the Loffoden Isles and Christianiafiord in 50-300 fathoms, 
and described as S. pentagonum. ‘The coincidence of the first 
and last of these specific names is curious. D. bicarinatum of 
Deshayes (a tertiary fossil) may also be referable to the genus 
Siphonodentalium. LD. bifissum of Searles Wood, from the Co- 
ralline 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‘Andrew. I 
suspected that D. difissum might be the tube of a young Teredo 
norvegica, on account of its having a septal process within the 
posterior orifice: at all events my remark is justified by the 
affinity which exists between the Teredinide and the Soleno- 
conchia. 
The second species of this class is 
Cadulus subfusiformis, Sars 
(Siphonodentalium subfusiforme, 1. c. p. 21, figs. 36-44), having 
a Norwegian distribution equally extensive with that of S. Lofo- 
tense, but attaining a greater depth, viz. from 50 to 300 fathoms. 
I noticed specimens among the fossils collected last year by 
Messrs. Crosskey and Robertson in a raised sea-bed at Barholmen, 
near Christiania. It occurred on the Unst ground, in 80-90 fa- 
thoms, and was apparently not rare. Mr. Peach detected a spe- 
cimen in looking over some sand which I dredged there in 1864 ; 
this I at the time regarded as a Ditrypa. The margin of the 
posterior orifice has two slight indentations or notches, one on 
each side; and Sars’s statement that the margin is entire was 
perhaps founded on imperfect specimens. C. subfusiformis may 
be known from C. gadus not only by its much smaller size, but 
also by having the greatest width or diameter in the middle 
(instead of in the upper or anterior part), and by the posterior 
or narrower part being abruptly curtailed. C. gadus is awl- 
shaped, and has a tapering extremity. C. subfusiformis is 
gibbous. Whether C. gadus inhabits our seas is questionable. 
Montagu says*, ‘“ This is a pelagic species, found in many parts 
of the British Channel, and is known to mariners by the name 
of ‘hake’s tooth,’ who frequently find it within soundings, 
adhering to the log-line (as we are informed), but most likely to 
* Test. Brit. i. p. 496. ie 
