^6 Mr. H. J. Carter on Teichonellidse. 



tusely angular, convex or undulatory above (PI. II. fig. 1, 

 a a a), irregularly notched below, where the projecting parts 

 may be expanded into pedal points of attachment (fig. 1, e e) ; 

 surface uneven, interrupted here and there, on both sides, by 

 a proliferous lamina, which originates from the upper margin, 

 and may pass, after a short distance, insensibly into the sur- 

 face of the parent lamina (fig. 1, hh)^ or grow into greater 

 dimensions foliaceously or cactus-like (fig. 1, c). Pores invi- 

 sible to the unassisted eye, scattered over the surface thickly 

 and generally. Vents slightly marginated, naked (that is, 

 without fringe round the mouth), arranged more or less in 

 single line along the margin only (fig. 1, ddd^ and fig. 2, 

 a a a), variable in size, the largest about l-48th inch in 

 diameter and l-8th inch apart. Internal structure minutely 

 areolar, compact, traversed vertically by branched excretory 

 canal-systems, which terminate respectively in the vents just 

 mentioned (fig. 3, a «) ; largest canals, viz. those approaching 

 the vents, about l-32nd inch in diameter. Spicules of two 

 forms, viz. triradriate and quadriradiate. Triradiate of two 

 sizes, viz. small (fig. 4, a) and large (fig. 4) , both equian- 

 gulate and equiradiate ; rays straight, smooth, and sharp- 

 pointed ; the former, which is the staple spicule of the sponge, 

 only one third of the size of the latter, which, although less 

 numerous, is still plentifully distributed throughout the mass ; 

 ray of small triradiate about l-200th inch, that of the large 

 one l-50th inch long. Quadriradiate also of two sizes, viz. 

 small (fig. 4, b) and large (fig. 5) ; the former about the 

 size of the small triradiate, and confined to the excretory 

 canals, where its fourth arm (fig. 4, c), instead of being 

 straight and equal in size like the rest, is curved and smaller, 

 projects into the excretory canal, and is turned towards the 

 vent. Large quadriradriate exceeding in size the large tri- 

 radiate of the mass, confined to the surface, where three of its 

 rays are horizontal (fig. 5, a), equiangulate and equiradiate, 

 while the fourth or shaft (fig. 5, b) is much smaller and ver- 

 tical ; large rays smooth, sharp-pointed, and slightly curved 

 inwards, applied to the surface of the sponge; fourth or small 

 ray straight, smooth, and sharp-pointed, projecting into the 

 interior ; large quadriradiates most plentiful over the upper 

 part of the lamina, where their centres are frequently'- not 

 more than 1 -180th inch apart, and, presenting a dark colour 

 from the light passing into the fourth arm, may be easily mis- 

 taken for the pores, from which, however, they may be distin- 

 guished by being larger and more or less triangular, while the 

 pores are smaller and round. Size of entire specimen (fig. 1) 

 3-^ X 2^ X 1 inches; length of margin of largest lamina (fig. 1, 



