
226 On the Genus Paleacis. 
1. P. cuneiformis, |= Sphenopoterium cuneatum, |Compressed, cuneate, longer 
J. Haime. 8 OW. than wide ; base sharp ; cells 
2. P. obtusa, M. &|=S. compressum, M. & W.* ; 
W. 
3. P. eyclostoma, 
Phill. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
9. 
P. cymba, v. Seebach ; P. 
umbonata, v. Seebach. 
=Propora? cyclostoma, Ed. 
& H.; Sph. enorme, M. & 
W.; Sph. enorme, var. de- 
pressum, M. & W.; Ptycho. 
laxus, Ludw.; Paleacis 
enornus, v. Seeb. ; P. laxa, 
Kunth; P. cyclostoma, De 
Kon.; P. compressa, De 
Kon.; P. cyclostoma, var. 
Koninckii, EH. & N. 
arranged alternately on each 
lateral edge, and directed 
obliquely outwards and up- 
wards. 
Abruptly cuneate below, wider 
than high; basal edge 
slightly sinuous in the mid- 
dle and carina-like, from 
which the sides expand ra- 
pidly upwards, &c. 
Attached to foreign bodies by 
a broad base, concentrically 
wrinkled. Colony depress- 
ed and lobed, of many cups, 
or elongated and laterally 
prolonged. Cups with a 
number of microscopical 
granules arranged in verti- 
cal rows; floors of the cups 
ornamented with granules. 

EXPLANATION OF PLATE XII. 
. A small specimen of Paleacis cyclostoma attached to the stem of 
a Crinoid, of the natural size. 
. Another specimen of the same, viewed from above, of the natural 
size. 
. Under surface of a large specimen of the same, in which the 
peduncle of attachment has been a narrow one, of the natural 
size. 
. Portion of the surface between two of the cups in a specimen 
devoid of large pores, magnified. 
. Portion of the surface between two of the cups in a specimen in 
which arge pores are present, magnified. 
. Portion of the under surface, showing pores and elongated aper- 
tures, magnified, 
. Thin section of a colony of P. cyclostoma, attached to the shell of 
a Gasteropod, and enlarged eight diameters, showing the dark 
matrix filling the cups (a), the trabecular tissue (c), and the 
compact tubulated tissue (6) which forms the floors of the 
cups. 
. A portion of the same, enlarged twenty-five diameters, showing 
the matrix filling the cup (a), the compact tubulated tissue in 
the floor of the cup (0), and the denser but still tubulated 
tissue bounding the lacunze of the deeper vesicular tissue (c). 
A specimen of P. cuneiformis, viewed from the front, of the 
natural size. 
Fig. 10. The same viewed sideways, showing the cups. 


* Meek and Worthen appear to have thought it very probable that 
this might be only a variety of their S. obtusum. 
