340 SPECIES OF THE SYSTEMA. 
clathrus; for it is still difficult to pronounce upon the ad- 
visability of its resuscitation. 
Turbo ambiguus. 
The epithet ambiguus may either relate to doubts of its 
generic allocation, or, more probably, of its essential indi- 
viduality. It may be presumed, from the “ simillima clathro” 
of the description, that this shell belonged to the genus Sca- 
laria, but to what species it should be referred is still uncertain. 
Nothing in the cabinet of our author corresponds satisfactorily 
with the features he has attributed to it, and no manuscript 
addition has been bequeathed to us by him, so as to further 
elucidate the matter. Unaided by any pictorial synonymy, it 
could not be expected that naturalists should have indisputably 
recognised an object so briefly defined. Gmelin has merely 
transposed and abridged the original words ; Schréter described, 
yet did not figure his ideal; Dillwyn was unable to increase our 
knowledge of it. Karsten has considered that figures 1435, 6 
of the fourth volume of Chemnitz represent it; a conclusion 
not borne out by either his own description or the cited 
drawings. In the ‘Synopsis’ of Menke mention is made of the 
Scalaria ambigua of Linneus; but as no details are given we 
are not much enlightened thereby: in the recent Monograph of 
Scalaria by Sowerby the species is passed over in silence. Yet 
the recorded features “2 seu 3 lineis ferrugineis secundum 
anfractus pictis: basi umbilicata,” and 30 ribs, as we learn from 
the contrast of it to clathrus in the concluding paragraph of the 
preceding species, are not of ordinary combination in that 
genus; so that it is not impossible that some member of that 
genus may be found that will precisely and exclusively agree 
with the Linnean description. The S. lineolata of the ‘'The- 
saurus’ fairly enough agrees with the specified features, and the 
S. lyra of the same work has already been proposed (despite of 
the expressions “ turrita” and “ simillima clathro”’) as its re- 
presentative : neither of the two, however, have been discovered 
in the Mediterranean (the stated locality); so that such an 
identification would savour too much of conjecture to be 
recommended. 
