8 
MUSEUM BULLETIN NO. 5. 
the great development of the sheath zone in the form under 
consideration, it does not seem proper to refer it to Beatricea , 
and the following new generic name is, therefore, proposed. 
Genus CRYPTOPHRAGMUS nov. 
( Kryptos , concealed; phragmos, partition .) 
Colonial organisms, presumably Hydromedusae, of elongate > 
upright, unbranched form, small diameter, and slight taper. 
Skeleton consisting of internal camerate tube with distinct 
wall, the tube crossed by irregularly spaced partitions which 
are convex upward, and further strengthened by a deposit 
of incomplete partitions (cystose material) on the inner side of 
the wall of the tube. The inner tube enveloped by concentric, 
often slightly separated sheaths of calcareous material, the 
sheaths traversed by numerous circular openings at right angles 
to the long axis of the colony. The sheaths extend over the 
upper end of the inner tube, which may be enlarged and bulb- 
like. Type, Cryptophragmus antiquatus sp. nov. 
CRYPTOPHRAGMUS ANTIQUATUS Sp. nov. 
Plates I-IV. 
Since I have not differentiated the rather numerous varieties 
that are found in the locality at Carden, the generic description 
will serve also for the species. Should Ulrich’s Beatricea gracilis 
prove to belong to this genus, it may be necessary to enter 
into the question of specific characters. At present, Beatricea 
gracilis has the status of nomen nudum. It may be possible to 
differentiate species on the basis of the relation of the diameter 
of the inner tube or support to the total diameter of the colony, 
in which case the specimens figured on Plate I, figure 2, would not 
belong to the same species as those shown in figures 3 and 4, Plate 
I, and 1 and 2, Plate II. In view of this contingency, I have 
designated the specimens with the large tubes as the types of 
the species C. antiquatus , and, in particular, would designate the 
most complete specimen Plate I, figure 1, as the holotype of the 
species. 
Some of the specimens have the axial tube 15 mm. in diameter 
