rOLYCLINUM AUEANTIUM. O 



(1842), p. 292,] pi. i, f. 6, and pi. iii, f. 4; FOIJBKS & 

 HANLEY Brit, Moll. I [1848], p. 14, pi. A, f. 3, and pi. B, 

 f. 3 ; ALDER & HANCOCK (?) in Trans. Tyneside Nat. Field 

 Club, I [1848], p. 203; [CocKs in Kep. II. Cornw. Polyt. 

 Soc. for 1849 (1850), p. 74; GOSSE Man. Marine Zool. II 

 (1856), p. 32, f. 45; H. & A. ADAMS Uen. Recent Moll. 

 II (1858), pi. cxxxiv, ff. 3, 3 a; ANSTED & LATHAM Channel 

 Isl. (1862), p. 219]. 



Colonies [coriaceous,] sub-globular, a little depressed, 

 and attached by a narrow base (PL LI, fig. 5) ; some- 

 times slightly ped uii dilated ; frequently associated in 



.- . . . 



.. . 



FIG. 88. Polydinutn aurantium. About twice natural size. (M. 

 Edwards,* pi. iii, f. 4-.) c, branchial apertures, i, common cloacal 

 oi'ifice. 



groups of unequal-sized masses connected together by 

 creeping fibres (PL LI, figs. 1 and 2) ; colour yellowish, 

 varying from pale yellow to yellowish orange. Incli- 

 r'uliials (PL LI, fig. o) forming systems arranged in 

 elliptic curves around large excretory orifices with 

 smooth rims (fig. 88). Branchial aperture (fig. 89) 

 with six lobes or small digitate prolongations ; atria I 

 with a rather long languet. Thorax cylindrical, 

 connected with the abdomen by a short peduncle. 

 Branchial sac with thirteen rows of meshes. Abdomen 



* This and all other figures after Milne Edwards are copied from his work 

 quoted in the synonymy. 



