38 



DR. W. RAE SHERRIFFS ON EVOLUTION 



§ 5. Before proceeding to considei^ the specific cliai'acters 

 selected for examination and criticism, it will be well to recognize 

 clearly the typical architecture of a Dendronephthya polyp as 



Text-figure 4. 



I Sp'/cu/es o/" 

 y tentac/e 



J 



/n term ecf /'ate 

 spt'cu/e 



Anthocod/oi/ 



spi'cu/es 

 (/pa/'rj Q) 



Crown (2) 



A ccessory 

 ' spi'cu/e 



Supporting 

 bund/ e 



© 



iLsrge Cnja/n) 

 \ spi'cu/es 



Armature of lateral point of Polyp. 



regards its external spiculation (text-fig. 4). When every por- 

 tion is represented, the ascending order above the polyp stalk 

 is as follows : — 



(1) The spicules of the supporting bundle (Stutzbiindel), several 



of which are usually very large (often up to 3 or 4 mm. in 

 length) and often projecting beyond the polyp for a 

 distance of 0"5-l-5 mm. It is useful to distinguish in the 

 supporting bundle the main spicules and the accessory 

 spicules, the latter often mingling gradually with those of 

 the polyp stalk. 



(2) The "crown," consisting of a few rows, very commonly 



three, of spicules arranged horizontally round the base of 

 the anthocodial part of the polyp. 



(3) The anthocodial armature, in the strict sense, which 



consists mainly of the spicules entering into the com- 

 position of each of the eight points. Between each pair 

 of points tiny spicules are frequently found. These I term 

 intermediates and discount their value because they are 

 so variable. 



(4) Yery minute spicules on the tentacles, the nature and 



number of which seem to be quite unimportant. 



