336 THE VOYAGE OF H.M.S. CHALLENGER. 



uniform distribution. These occur at intervals of 2 to 3 mm., and are not otherwise 

 remarkable, except as local condensations of the network of beams. Both on the beams of 

 the wide meshed part of the framework, and on the outer surface of the knots, small 

 simple hexacts occur fused together in variable numbers. All the beams of the frame- 

 work and the small fused hexacts are more or less richly beset with small tubercles. 



From what has been said there can be no doubt that the specimens in question 

 belong to the species Ficldingia lagettoides, Sav. Kent, which Saville Kent found on a 

 specimen of Loj'thoheUa at Cezimbra, Portugal, and which he has figured and described. 

 But it is to be regretted that in many parts of the present specimens the remarkable 

 blistered rind, which is of several layers, is insufficiently preserved for accurate 

 examination. From the fragments, however, it may be seen that we have to deal with 

 lattice-like lamellfe, which exhibit the crossed tangential rays of numerous pentacts, in 

 which the fifth ray projects inwards. Between these pentact rays, which are remarkable 

 for their distinct axial canals, there extends a more or less well-developed, in part very 

 narrow-meshed, network of connecting beams without central canals, and provided with 

 rounded meshes. This is similar to what is found in the basal plate of many fixed 

 Hexactinellida, and in the regions of contact between these and sofid foreign bodies. 

 Since the free outer surface is covered with sand and other extrinsic elements, the 

 supposition is confirmed that we have here to deal with a dermal skeleton altered by an 

 admixture of foreion bodies. 



Among isolated spicules several apparently typical forms occur. It is not possible to 

 determine with certainty their normal arrangement or stratification. In addition to 

 various strong uncinates (PI. XCVII. fig. 9), simple straight smooth diacts frequently 

 occur. These exhibit a central swelling or four cruciately disposed knobs, and their 

 two extremities form a point which arises by a process of jjitting (PI. XCVII fig. 8). 

 In addition to simple smooth and delicate hexacts (PI. XCVII. fig. 7), oxyhexasters 

 occur, which have several or all of their rays forked. The principal ray usually remains 

 very short (PI. XCVII. fig. 6), and sometimes, indeed, it is so much abbreviated that the 

 terminal rays appear to rise almost directly from the node of intersection, and in this 

 way a simple star with ten or more rays results (PL XCVII. fig. 3). Discohexasters 

 with two or more fine long terminals on each of the short principal rays, and with 

 marginally toothed somewhat convex terminal discs, are tolerably frequent (PL XCVII. 

 fig. 4). 



The scopulse, which probably belong to the dermal skeleton, exhibit four strong 

 almost parallel teeth, which are beset with barbs, and are slightly knobbed, or terminate 

 without any swelling. The teeth spring from the conically thickened extremity of the 

 rough and pointed shaft. Less frequently the teeth diverge in the manner represented 

 on PL XCVII. fig. 5. 



