46 
much consisteney, although it contains very strong fibres; this may 
be the reason that Bowerbank only saw flat fragments. The sur- 
face is corrugated and rough by protruding spieules (fig. 153, pl. 
IV). The colour is (in spirit) light gray. 
The skeleton consists of strong main fibres which give off thinner 
and thinner branches. The spicules are the following: 
1°. Tr, ae. I. (ne. 99): 
2°. (tr°.) ac. (f) NB. (fig. 100, fragment). Bowerbank gives the 
following description of these curious spieules: „They are large 
and long, somewhat slender, and slightly fusiform; but their pecu- 
liarity consists in an irregular constrietion of the shaft near its 
basal extremity. This commences at about one diameter of the 
largest part of the shaft from the extreme base, and continues for 
from one to three diameters up the shaft, which tben gradually 
inereases in its diameter as in the usual form of a fusiform spieu- 
’ 
lum”.. Misled by Bowerbanks illustration I have formulated this 
spieule ac. ac. NB.!) But, having now seen such curious spi- 
cules in nature I am convinced that it are modifications not of 
the acerate, but of the acuate type. My fault is that I have over- 
looked that Bowerbank himself held this opinion. He says: „The 
sudden constriction of the shaft near its base gives that portion of 
it the appearance of an elongo-curvato-spinulate termination; but in 
some of the spieula where the constrietion is absent or very slightly 
produced, the spinulate character is entirely obsolete”. 
3°. ac?. Bowerbank observes that he has seen small spicules, 
„unmistakably visible, but not sufliciently so to determine accura- 
tely whether the form was acuate or acerate, although submitted 
to a linear power of 660”. As far as I could see they are acerate, 
lying in bundles. This kind of small spieules („trichites’’, Soll.) 
are observed in many Esperia’s. 
4°. rut. rut. [figg. 101 and 103]. There are two kinds of pal- 
mato-anchorates, the shape of which does not differ enough from 
Bowerbank’s illustration to establish a new species. 
1) 1. c. pag. 145. 
