FARREA OCCA SCUTELLA. 
121 
chiefly triangular meshes (Plate 26 , fig. 16). The marginal and middle-parts of 
the skeleton-net of the body-lamella (Plate 26 , figs. 8, 9, 14) consist of a single 
layer composed of longitudinal and transverse beams. The former are in some 
places curved, in others straight, and spread out towards the margin of the 
lamella in a fan-shaped manner. Here and there they divide into two equal 
branches, which, at first, diverge at an angle of about 30°, but very soon become 
parallel ; thus the number of the longitudinal beams increases towards the margin 
of the body-lamella. The transverse beams are vertical to the longitudinal ones 
and accordingly also in some places curved, in others straight. All the beams 
of this network are quite smooth. The longitudinal ones are mostly 73-80 n 
thick, the transverse 75-90 tx. The meshes are mostly square and rectangular, 
more rarely quadratic, and exceptionally (where the longitudinal beams branch) 
triangular. The rectangular ones are 280-510 n long and 200-400 p. broad. In 
some places this network is remarkably regular (Plate 26 , fig. 8). From each 
node of this network two thorns, 32-45 m thick at the base, arise in opposite 
directions. Both are vertical to the surface in which the network extends. 
One is directed dermally, the other gastrally. These thorns are fairly straight, 
either conic or thickened near the end, and covered with protuberances. At the 
base these thorns are broad, rounded, and 6-8 m high; towards the end they be- 
come smaller and much more slender. 
Of the loose spicules the uncinates and clavules with short teeth are very 
rare and also the hexactines rather scarce. The other kinds of loose spicules, 
particularly the oxyhexasters, are abundant (Plate 26 , fig. 8). The fragmentary 
condition of the specimens renders it difficult to ascertain the position of these 
spicules in the sponge. I can say, however, that there is no reason to assume 
that they are arranged otherwise than in the type of this species where their 
position has been described by Schulze. 1 
The loose hexactines (Plate 25 , fig. 26) are 110-190 n in total diameter, and 
have straight, conic, spined rays usually 3.5-4 /z thick at the base. 
The pentactines (Plate 26 , figs. 8a, 15; Plate 27 , fig. 6a) have regularly 
arranged lateral rays, usually 180-255 m long. The lateral rays of the same 
spicule are as a rule somewhat unequal. The difference in length between the 
longest and shortest is usually 15-30 ^ • Very rarely one lateral ray is greatly 
reduced in length, only 120 ^ long, and terminally thickened. When that is the 
case this difference is of course much greater. The lateral rays are straight or, 
more frequently, slightly and uniformly curved, concave to the proximal ray. 
F. E. Schulze. Rept. Voy. Challenger, 1887, 21 , p. 277 ff., pi. 71-73, 76, figs. 1-3. 
