374 HYALONEMA (PHIALONEMA) PATERIFERUM. 



of the anchors of these spicules; n, the length of the small micramphidiscs ; and 

 0, the average proportion of the length to the breadth of the anchors of these 

 spicules. 



a, The length of the distal ray of the ordinary pinules varies in the forms 

 A , B, and F between about the same limits. The other forms differ, in respect 

 to this dimension, from these and from each other, b, The distal rays of the 

 ordinary pinules are, in the forms A, B, E, and F, usually about 5 m thick at the 

 base, in forms C and D considerably thinner, c, The shortest lateral rays of the 

 ordinary pinules are in the forms A and B 30 m long, in the forms E and F 24- 

 26 n, in form D 16 fx, and in form C only 13 fi. d, The diameter * of the micro- 

 hexactines varies in the forms A, B, and E between fairly equal Umits (55-160 m)- 

 In the forms D and F the largest microhexactines are smaller, only 128 m in 

 diameter in the former and 138 ^ in diameter in the latter. In form C these 

 spicules are much smaller still, e, The length of the large macramphidiscs 

 varies between similar Imiits (100-235 m) in the forms A, B, C, and F. In the 

 forms D and E the largest large macramphidiscs are 300 n or more long, and 

 also have a much greater average size. /, The shafts of the large macramphi- 

 discs are thickest in forms C and E, thinner in form D and F, and still thinner in 

 form A. In form B this dimension is not known, g, The average proportion 

 of anchor-length to anchor-breadth is in the forms E and F 100 : 361 and 100 : 

 363 respectively; in form C 100 : 339, and in form D only 100 : 298. In the 

 forms A and B studied by Wilson it is not known. Since, however, Wilson 

 (Inc. cit.) states that in the former the anchor-length is one seventh and in the 

 latter one fifth of the length of the whole spicule, which is said to be the same 

 in both, it may be assumed that these two forms differ in respect to this anchor- 

 proportion from each other, h, The small macramphidiscs are in the forms A, B, 

 C, and D fairly equally long, in the forms E and F they are longer, i, The thick- 

 ness of the shafts of the small macramphidiscs is greatest in form E, equal and 

 smaller in form C and F, and still smaller in form D. In forms A and B this 

 dimension is not known, k, The average proportion of anchor-length to anchor- 

 breadth of the small macramphidiscs is in the forms C, E, and F 100 to over 250, 

 in form D only 100 to 162. In the forms A and B this anchor-proportion is not 

 known. I, The length of the large micramphidiscs varies in the forms il, B, and 

 E between nearly equal limits (47-80 yu), and is in form E most frequently about 

 73 M- In form C these spicules are not so large, most frequently 57 n long, and 

 in forms D and F nearly equal and still shorter, most frequently 52 and 53 ^ 



' In the forms .4 and B, where only the ray-length is given, the double ray-length is taken as the 

 diameter. 



