144 
Fig. 22. Clathria Mortensenii, nov. sp. a, styli; b, 
styli; c, isochelae; d, toxa. 
,0 the free surface; so they are very short, on account o the very 
insignificant thickness of the sponge, only a few 
fL these fibres radiate at right angles numerous small sp.ned 
styli. In many cases one 
cannot discern distinet 
fibres; only long styli 
are seen placed per- 
pendicularly towards the 
surface,making it hispid, 
while small spined styli 
are lying parallel with 
the surface. Many toxa 
^ are scattered irregularly 
about in the tissues, 
while the chelae only 
are found in smaller 
numbers. 
Spicules: (fig. 22 a d) 
1 . styli, big and stout, 
slightly bent at the first 
third or fourth, thick- 
est at the base, evenly 
tapering to a fine point; 
base spined; length very 
mueh varying, from 182 
-520 « falling into two groups: lengths most commonly about 
450 /r and 260 thickness about 20 2. styli, smaller spmed 
all over, shape as the big ones, though somewhat more clumsy 
Lgth about 143 thickness about 15-18 Many ^evelopmental 
forms, especially of the bigger stylt. 3. isochelae, very , 
median third of the shaft straight, then bending towards the end 
the same length and breadth as alae, formed as a broad 
Hangir the angles of which are a little rounded. Length ca. 16, 
" . br..d,h4. .0.., v.r, ..g..«..? ...W- 
thin; length somewhat varying about ca. 100 p. 
