HYALONEMA (OONEMA) BIANCHORATUM PINULINA. 



323 



a stout knob or two are observed also on other parts of the shaft (Plate 85, 

 figs. 1,2). The single large spine on the central tyle is, in the normal large 

 macramphidiscs, sometimes 21 ^ long and 14 ju thick. I have never seen more 

 than one such large spine on a normal spicule of this kind. In a few abnormal 

 large macramphidiscs I observed (Plate 85, fig. 3) one or two cliisters of verticils 

 of projections arising some distance from the middle of the shaft. These had a 

 maximum length of 45 m, and were inclined or curved towards the centrum. 

 They appear to be supernumerary anchor-teeth. 



The proportion of the terminal anchor to the total length of the whole spicule 

 is (in both specimens together), as stated above, 1 to 2.1-3.9, an average of 1 : 3.2. 

 The difference between total length and anchor-length is the greater the larger 

 the spicule. In the large macramphidiscs 400 ^l and more in length the above 

 proportion is 1 : 3.2-3.9, in those under 300 ix in lengtli 1 : 2.1-3. 



The anchor-teeth are about 30 > broad and pointed at the end. They arise 

 nearly vertically from the shaft and are quite strongly curved in their proximal, 

 and straight in their distal part. Their total curvature is such that their end- 

 parts diverge at an angle of 12°-22° from the shaft. 



The chief dimensions of the small macramplddiscs (Plate 83, fig. 45c; 

 Plate 84, figs. 3-13, 26-32) are: — 



