436 SPECIES OF THE SYSTEMA. 
Dentalium aprtwten. 
The shell (Desh. Monog. Dent. pl. 2, f. 18) selected by natu- 
ralists as the representative of this species, agrees in all but 
colouring, being of a rather pale green hue in place of white. 
As the loss of colour is no rare circumstance in dead specimens, 
and no known Dentaliwm answers better to the description, the 
traditional recognition should not be lightly rejected; it is 
desirable, then, to retain the name for that species, with a 
“probably” appended, in referring to the ‘Systema.’ Perhaps, 
too, the circumstance of there being a specimen of it preserved 
in the Linnean collection, where no other shell corresponds 
more fairly with the definition, and the record of the presence 
of aprinwm in his cabinet by the younger Linné may be held 
corroborative : it was manifestly, however, inserted subsequently 
to the constitution of the species. The Linnean appellation 
has, likewise, been bestowed upon D. octogonum (by Mawe): 
“ decem-angulata,” however, is ill suited to express the cha- 
racter of that wéll-known tusk-shell. 
Dentaliun Dentalis. 
The cited figure of Rumphius is almost too rude for recogni- 
tion, yet has somewhat the aspect of D. octogonum, which does 
not answer correctly to the description. As the shell is declared 
to be present in the Linnean cabinet, and only a single species 
in the collection corresponds with the assigned characteristics, 
there can be no doubt of its typical authority. The individuals 
alluded to have experienced several interruptions (fractures) in 
their growth ; hence the expression “‘interrupta.” They appear 
to belong to the Dentaliwm dentale of authors (Reeve, Conch. 
Syst. 1. pl. 130, f. 2), but are rather more coarsely ridged than 
usual. The correctness of the stated locality greatly facilitated 
the established identification. 
