53 



SPECIES OF ACA-NTROGOnGlA~co7ifmned. 



Polyps. 



In twos, threes, or 

 in loose spirals. 



Opposite or spir- 

 ally, but3'ounger 

 polyps interpo- 

 lated. 



Axis. 



Hornv. 



Horny, cham- 

 bered, brownish- 

 yellow in older, 

 yellow in 

 younger parts. 



Yellowish -brown, 

 strongly stri- 

 ated. 



Alternately on two Brownish-yellow, 

 sides of the stem 

 and branches. 



Yellowish-brown, 



Distant on stem, 

 more numerous 

 on the branch- 

 lets, irregularly 

 alternate, pro- 

 minent. 



Spicules. 



Spindles and quadri- 

 radiate forms. 



Spindles with few 

 warts, tri- and 

 quadri - radiate 

 stars and golf- 

 club forms, with 

 long shaft free, 

 and head with 

 rough warts ; also 

 a few irregular 

 sex- and quinque- 

 radiate forms. 



In ca;nenchyma, 

 small, rough, 

 irregular, and 

 rather large, very 

 roughly warted, or 

 sjiinulose fusiform 

 spicules, fre- 

 quently curved. 

 In calyces, slender, 

 elongated, warty 

 fusiform spicules, 

 either straight or 

 curved. 



In canenchy ma, 

 acute fusiform 

 spicules, often S- 

 shaped, similar in 

 polyps. 



In ccenenchyma, 

 white rough 

 curved fusiform 

 spicules. 



Colour 



Greyish-white. 



Ash-grey. 



Grey. 



Notes. 



Similar to A. r: 

 in mode of branch- 

 ing and in the 

 arrangement of 

 the polyps, but 

 like A. muricata, 

 Hiles, in the dis- 

 position of the 

 spicules on the 

 calyces. 



Closely related to 

 A. armiita, but 

 differs in having 

 smaller calyces, 

 with longer 

 spicules, and in 

 form of ccenen- 

 chyma spicules ; 

 and also differs 

 from A. aspera 

 in not being 

 hispid. 



Studer doubts if 

 Hedlund's A. as- 

 pera should be 

 referred to this 

 species. 



