260 SERTTJLABIID^:. 



I therefore blend the two groups under the old Linnaean 

 name. 



Without the examination of a much larger number of 

 foreign species, the genera of this family cannot be defined 

 with certainty and precision; and the present grouping 

 must be accepted as, to some extent, provisional. 



Sertularia is a cosmopolitan genus, and a large number 

 of species have been described. 



With opposite calycles [Dynamena, Lamx.]. 



1. S. PUMILA, Linnaeus. 



" SEA-OAK CORALLINE," Ellis, Corall. 9, pi. v. figs, a, A. 



SERTULARIA PUMILA, Linn. Syst. 1306; Pallas, Elench. 130; Esper, Pflanz. 



Sert. t. x. figs. 1, 2 ; Lamk. An. s. Vert. (2nd ed.) ii. 145; 



Lister, Phil. Trans. 1834, 371, pi. viii. fig. 3; Johnst. B. Z. 



66, pi. xi. figs. 3, 4. 

 DYNAMENA PUMILA, Lamx. Bulletin Soc. Philomatique, 1812, iii. 184; Cor. 



flex. 179 ; Flem. Brit. An. 544 ; Agassis, N. H. U. S. iv 355. 

 SERTOLARA PICCINA, D. Chiaje, An. s. Vert. Nap. iv. 142. 



Plate LIII. fig. 1. 



SHOOTS crowded on the creeping stolon ; STEM straight or 

 gently curved from base to tip, simple or ramified; 

 branches opposite, and in luxuriant specimens them- 

 selves branched ; both stem and branches divided by 

 joints into short internodes, each of which, with its pair 

 of calycles, forms a V -shaped figure; HYDROTHEC^E op- 

 posite, shortly tubular, free above for about a third of 

 their length, narrowed towards the aperture, which is 

 bent outwards and more or less cleft and mucronated ; 

 GONOTHEC^: (female) irregularly ovate, subsessile, with a 

 tubular rim ; (male) more slender and regularly oval. 



S. PUMILA, the commonest of our littoral zoophytes, covers 

 the fronds and stems of the various larger Fuci with dense 

 miniature forests, and occurs on all parts of the coast. It 



