

86 



THE SPONGES. 





A very few pinules, having the peculiar character shown in Fig. 6, 

 Plate 9, are present, some at the surface, others caught in the skeletal 

 reticulum. The distal ray is stout, solid, and covered with exceedingly 

 small, sharp scales, except at its lower end, which is smooth. The tan- 

 gential and proximal rays are about cylindrical, slender, and smooth, 

 except near the end, where the ray is roughened. The distal ray is 

 130 fi long, with a greatest thickness of 56 /x. The tangential rays 

 measure 100 p x 4-5 /x ; proximal of same thickness as the tangentials, 

 but longer. 



Slender, smooth, nearly cylindrical oxydiacts, 6-8 /x thick, are found 

 here and there lodged in the dictyonal framework. The spicules are 

 always broken, but the length is often over 0.5 mm. 



Oxyhexasters (Fig. 7, Plate 9) with smooth slender rays are present 

 in some abundance in the skeletal framework, often occurring in clumps. 

 The terminals, of which there are commonly two to a principal, diverge 

 considerably, are very slightly curved, taper to fine points, and are larger 

 than the principals. The principal ray is about 12 /x, the terminals about 

 24 /x long. 



A very few scopulae (Fig. 8, Plate 9) are present, all of the same 

 type. It is of course uncertain whether they belong to the sponge. The 

 shaft is smooth, tapers gradually to a point, and measures 700 /x x 10 /x. 

 There are four terminal rays, 130 /x long, with a basal thickness of 12 /x. 

 The terminals are straight, smooth, taper conspicuously from the base 

 to the apex, which is rounded and scarcely enlarged. The spicules, like 

 the whole skeleton, have evidently lain long in the water, and the axial 

 canals are very large and distinct. The latter, which are shown in the 

 figure, are of some interest as bearing upon the morphology of the 

 spicule. From the axial cross which lies immediately below the termi- 

 nals, there is prolonged in one direction the canal of the shaft. On the 

 opposite side canals are prolonged for a short distance into the terminal 

 rays, and end in rounded extremities. 



i 



Schmidt (1880, p. 38) conceives the scopula as a modified hexact, and 

 in cases where there are five distal rays interprets these and the shaft as 

 representing the six hexact rays. Schulze (1887, p. 34) argues against this 

 interpretation, and is disposed to regard the distal rays (teeth) as com- 

 parable with " the terminal rays of the rosettes." The arrangement of 

 the axial canals in the scopulae here described supports Schulze's inter- 





