SEBTULARIA PUMILA. 261 



is usually of very humble size, not rising to a greater 

 height than half an inch. In favourable situations, how- 

 ever, it attains a more luxuriant growth, sending up shoots 

 of twice or three times the height, which are variously 

 branched. Agassiz says that the specimens obtained near 

 low- water mark are commonly "the most luxuriant, and 

 more or less branching, while those at higher levels are 

 quite simple." 



S. pumila is of a dusky horn-colour and somewhat close 

 texture. The polypite, which is long, slender, and grace- 

 ful, has about 16 tentacles. The capsules are produced 

 abundantly both on the main stems and branches, and 

 often occur in continuous rows of considerable length. 

 The female contains a single sporosac, whence the ova, 

 which are very numerous"*, are discharged into an exter- 

 nal marsupium, protected by a gelatinous investment, in 

 which they complete their development. 



The breeding-season, according to Agassiz, extends from 

 May to September. 



Judging from the figures given by this author, there is 

 but little difference between the male and female gono- 

 thecse in shape, the former being somewhat slighter and 

 more regularly oval. S. pumila is one of the phospho- 

 rescent species. If a frond of Fucus on which it is growing 

 " receive a smart stroke in the dark, the whole coralline is 

 most beautifully illuminated, every denticle seeming to be 

 on fire"t- 



Hab. Between tide-marks, chiefly on the larger Fuel, 

 generally distributed. This zoophyte is met with on the 

 most barren shores. 



[Greenland (Fabricius) : Lofoten and Finmark, common 

 on Fucus vesiculosus, F. nodosus, and F. serratus, to the 



* ' Ovarium ovis plenissimum." Pallas. 



t Stewart, Elem. Nat. Hist, ii. 441, quoted in Johnston s Brit. Zooph. 



