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 ^ 

 thick, the transverse 75-90 //. The meshes are mostly square and rectangular, 

 more rarely quadratic, and exceptionally (where the longitudinal beams branch) 

 triangular. The rectangular ones are 280-510 ^ long and 200—100 n broad. In 

 some places this network is remarkably regular (Plate 26, fig. 8). From each 

 node of this network two thorns, 32-45 n 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 /n 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.^ 



The loose hexactines (Plate 25, fig. 26) are 110-190 ij. in total diameter, and 

 have straight, conic, spined rays usually 3.5-4 ^ tliick at the base. 



The pentactines (Plate 26, figs. 8a, 15; Plate 27, fig. 6a) have regularly 

 arranged lateral rays, usually 180-255 yu 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 /x. Very rarely one lateral ray is greatly 

 reduced in length, only 120 m long, and terminally tliickened. Wlien that is the 

 case this difference is of course much greater. The lateral rays are straight or, 

 more frequently, sUghtly and uniformly curved, concave to the proximal ray. 



' F. E. Schulze. Kept. Voy. ChaUenger, 1SS7, 21, p. 277 ff., pi. 71-73, 76, figs. 1-3. 



