HYALONEMA (PHIALONEMA) BREVANCORA. 359 



Shape and size. The larger fragment (Plate 55, fig. 1) is an irregular, porous, 

 flattened mass measuring 47 by 38 by 8 mm. The smaller one is only 22 mm. 

 long. 



The colour in spirit is dirty white. 



The skeleton consists of pinnies; hexactine, pentactine, and rhabd mega- 

 scleres; microhexactines ; and amphidiscs. In most of the pinnies in the 

 preparation the distal ray bears relatively very long spines; these pinules are 

 probably hypodermal or hypogastral. In some pinules these spines are very 

 short; these may be canalar. The hexactine megascleres are found in the 

 innermost part of the specimens; the pentactines are no doubt hypodermal or 

 hypogastral. The rhabd megascleres for the most part form bundles. The 

 microhexactines are numerous, and all of the same kind. Macramphidiscs and 

 large and small micramphidiscs can be distinguished among the amphidiscs. 

 The small micramphidiscs are abundant, the other amphidisc-forms rare. 



The (probably dermal and gastral) pinules with long-spined distal ray 

 (Plate 55, figs. 19-28, 30, 32, 33) are nearly always pentactine, very rarely 

 hexactine. The distal ray is straight, 70-89 ix long, and 3^ fi thick at the base. 

 It bears spines along its whole length. The spines on the proximal third or so 

 of its length are very small, straight, and directed obliquely upwards. The 

 distal and middle-parts of the ray are covered with spines very unequal in 

 length and in curvature, the large and the small ones being here irregularly 

 intermingled (Plate 55, fig. 19). Some of these spines attain a relatively very 

 considerable size, the largest being 18-54 n long and about 2 ju thick at the 

 base. The lower spines, both large and small, are usually nearly straight, and 

 very divergent (Plate 55, figs. 22, 25, 28). Farther up the short spines only are 

 like this, most of the longer ones being curved, concave to the ray. This curva- 

 tiu-e is not infrequently so great that their ends become inclined towards the 

 distal part of the ray (Plate 55, figs. 19, 21, 23). The spines are conic and sharp- 

 pointed. Some of the larger ones bear one or two, rarely more, secondary spine- 

 lets, usually 2-3 yu long, and inclined towards the end of the spines from which 

 they arise. The maximum thickness of the distal ray, together with the spines, 

 generally is 22-37 ju, rarely as much as 54 yu. The lateral rays are usually 22-37 fx 

 long, sometimes longer. They are cylindrical proximally, conic distally, pointed, 

 and beset with numerous oblique spines inclined towards the end of the ray. 

 These spines attain a very considerable size, particularly in the distal and 

 middle-parts of the ray. The lateral spines of these rays seem to be larger than 

 the others; they give to the contour of the ray, when seen from above, a markedly 



