ERYLUS SOLLASII. 

 DIMENSIONS OF TRIAENES. 



281 





Race 



all forms 



I 



Forms 



II 



III 



A 



B 



C 



D 



limits 



general 

 average 

 of the 

 largest 

 three 



general 

 average 



Rliabdome 



length 



of all the spicules 

 measured, /< 



210- 

 400 



140- 

 360 



220- 

 470 



200- 

 420 



210- 

 400 



180- 

 520 



140- 

 520 







a\erage of the 

 three largest, ,« 



373 



290 



397 



380 



380 



490 





385 





thickness 



of all the spicules 

 ineasuretl, /< 



10-15 



8-10 



10-22 



10-22 



12-20 



13-22 



8-22 







average of the 

 three thickest, /i 



13 



10 



18 



21 



19 



21 





17 





Simple clades 



length 



of all the spicules 

 measured, /< 



120- 

 215 



170- 

 280 



120- 

 270 



175- 

 270 



120- 

 240 



225- 

 300 



120- 

 300 







Branched 

 clades 



length of 

 main clades 



of all the spicules 

 measured, /( 





150- 

 230 



100- 

 200 



80- 

 140 



120- 

 185 



70- 

 270. 



70- 

 270 







length of 

 end clades 



of all the spicules 

 measured, /( 





30-50 



20-40 



60- 

 160 



10-00 



10- 

 130 



10- 

 160 







Cladome 



breadth 



of all th(> spicules 

 measured, /( 



IGO- 

 3.S0 



370- 

 460 



215- 

 490 



290- 

 470 



170- 

 450 



280- 

 550 



• 160- 

 550 







average of the 

 three largest, /( 



373 



413 



457 



450 



417 



530 





440 





Clade- (main clade) angle 



of all the spicules 

 measured 



89- 

 107 



100- 

 107 



89- 

 115 



86- 

 112 



95- 

 116 



98- 

 115 



86- 

 116 







average of all 



97 



103 



105 



101 



107.5 



107 







103.4 



This appears as a rudiment of a third ray. Most of the spines are conical,' 

 straight, and vertical, some conical and recurved (Plate 2, fig. 1), some irregu- 

 lar, cylindrical, terminally rounded or even thickened, and occasionally lobose 

 at the end. 



The acanthtylasters measure 10-38 n in diameter. Their size is in inverse 

 proportion to the number of their rays. To obtain a clearer insight into this 

 correlation I measured (and counted the rays of) 207 of them and took the 

 means of the diameters of those with the same ray-numbers. There is no 



