SERTULARELLA RUGOSA. 241 



4. S. RUGOSA, Linnaeus. 



" SNAIL TREFOIL CORALLINE," Ellis, Cor. 20, tab. xv. figs. , A. 



SERTULARIA RUGOSA, Linn. Syst. 1308 ; Pall. Elench. 126 ; Exper, Pflanz. 



Sert. tab. xi. figs. 1-4 ; Lamk. An. s. Vert. (2nd ed.) ii. 149 ; 



Johnston, B. Z. i. 63, pi. x. figs. 4-6. 

 CLYTIA RUGOSA, Lamx. Cor. flex. 204. 

 SERTULARIA PATAGONICA, D' Orb. Amer. M6rid. 

 SERTULARELLA RUGOSA. Gray, List of Brit. Mus. Radiata, 69. 

 AMPHITROCHA RUGOSA, Agassiz, Nat. Hist. U. S. iv. 356. 



Plate XLVII. fig. 2. 



SHOOTS small, gregarious, simple or very sparingly and 

 irregularly branched; STEMS ammlated at the base and 

 between the calycles; HYDROTHEC^E crowded, barrel- 

 shaped, strongly wrinkled transversely, narrowed towards 

 the quadrangular aperture, which is set obliquely and 

 looking outwards, and is furnished with four very minute 

 denticles and a quadripartite operculum ; GONOTHECJE 

 very large, ovate, strongly ribbed across, with a -^-toothed 

 aperture. 



THERE are two forms of this species. In the larger 

 and more luxuriant the creeping stem sends up nu- 

 merous crowded shoots, commonly less than an inch in 

 height, which are very scantily branched. They are bare 

 for some distance above the base, and strongly annulated. 

 Throughout the rest of their length they are covered with 

 the short barrel-like calycles, which are closely set, the 

 small intervening spaces being also more or less ringed. 

 The other is a dwarf variety. 



t/ 



The capsules are three or four times as large as the 

 hydrothecse. They are generally described as having a 

 tridentate aperture ; but there are, I believe, four teeth, 

 one of much smaller size than the rest. 



Hab. Most frequently parasitic on Flustra foliacca; 

 also on seaweed, zoophytes, &c., from low- water mark to 

 deep water ; common. 



R 



