MARINE POLYZOA. 49 



Porus cervinus minor, Marsiali, Hist. Phys. de la Mer, pi. 63. 



pi. 6. figs. 23, 24. 

 Eschara foliacea /3, Linn. Syst. ed. 10. 804. 



E. securifrons, Pall. Elench. 56. 



Flustra truncata, Linn. Syst. 1300 ; Mull. Zool. Dan. Prod. 253; 



Ellis and Soland. Zooph. 1 1 ; Berk. Syn. i. 214 ; ESper, 



Pflanz. Flust. t. 3. figs. 1,2; Oliv. Zool. Adriat. 274 ; Lamk. 



Anim. s. Vert. ed. 2. ii. 219 ; Grant, loc. cit. Ill ; Flem. Brit. 



Ani.n. 535 ; Johnst. Trans. Newc. Soc. ii. 264. pi. 12. fig. 1 ; 



Templeton, Mag. Nat. Hist. ix. 469; Johnst. Hist. Brit. 



Zooph. ed. 2. 344. t. 62. figs. 3, 4 ; Blainv. Diet. Sci. Nat. 



Ix. 415. 



Chartella securifrons, Gray, List of Brit. Rad. 104. 

 Hab. Britain (north and east chieliy). Australia! 



4. FLUSTRA OCTODON. PI. LVIII. fig. 5; & PL LVI. fig. 4. 



Cells slender, pyriform, elongated, with three or four strong, 

 hollow, pointed, incumbent, marginal denticles on each side, in 

 the upper half of the cell. Avicularium oblong, mandible semi- 

 circular. 

 Hab. Coast of Spain, M' Andrew. 



5. FLUSTRA DENTICULATA. PL LVI. fig. 7. & PL LVII. 



Cells much elongated, nearly linear ; a thick, hollow, upturned 

 spine on each upper angle. Margin beset throughout the en- 

 tire length of the cell with numerous thick, hollow, simple and 

 blunt or bifurcate dentate processes, which arise from the front 

 edge of the margin ; sides of the cell immediately within the edge 

 denticulate, with numerous minute, pointed denticles. Avicu- 

 laria conical ; mandible placed with its base oblique, point pro- 

 duced, acute. 

 Hab. Australia, B. M. 



Var. a. (inermis). PL XLIX. figs. 3, 4. 

 Without the larger anterior teeth, or with but very few. 



F. denticulata, Busk, op. c. i. 380. 

 Hab. Bass' Strait. 



The very curious dentate processes on the edges of the cells 

 render this species very conspicuous, but the total absence, or 

 nearly so, of these external appendages in some instances ren- 

 ders the aspect of various specimens so different, that it requires 

 some attention to perceive their identity. The peculiar form and 

 position of the avicularium, and the presence of the internal or 

 submarginal denticles, are the characteristic diagnostic marks. 



D 



