336 
has been unanimously agreed by all authors dealing with these 
species, also by Den dy himself, that C. calcarea is nothing but a 
synonym of brevidentis. I am not inclined to agree with this, and 
think that only the faet that Den dy failed to emphasize in a suf¬ 
ficient way the differences existing in the calcareous deposits of 
Fig. 26. Calcareous deposits of Cueumaria brevidentis and C. calcarea. 
a. Cups, in various positions, b. buttons of C. brevidentis; c. buttons, d. cups, from 
aliove and in side view (lowermost figure) of C. calcarea. a. and d. j b. and c. 
the two species caused Ludwig and, after him, the other authors 
to deny the specific validity of calcarea. 
In the general appearance it is certainly not easy to find charac- 
ters to distinguish the two species, at least in a preserved State and 
rather poor condition, as are, unfortunately, my specimens. The only 
noteworthy difference which I can find is in the colour, calcarea being 
perfeetly white, brevidentis generally of a faint blackish tint in the 
anterior end, mainly on the tentacles and the thinwalled, retractile part 
(the “introvert”). However, this colour is no quite constant feature in 
brevidentis and thus forms no quite reliable character. Whether any 
differences are to be found in the internal anatomy I am unable to 
ascertain on account of the unsatisfactory State of preservation of my 
material. In the shape of the calcareous ring I do notsee any marked 
difference between the two forms. But then the calcareous deposits 
offer so marked and constant characters that one may always at a 
glance tell one species from the other (cf. Fig. 26). 
