Valkeiua. ZOOPHYTA. SERTUL ARIADNE. 551 



ria cus. Linn. Syst. i. 1311. Pall. EL 125. Abild. Zool. Dan. t. cxvii. 



f. 1, 2, 3 — Valkeria cus. Flem. Wern. Mem. iv. 485. t. xv. £ 1 On 



Corallines in deep water. 



Height seldom above two inches ; several stems usually arise from the 

 same base, filiform, jointed, waved, and support the branches and cells bifa- 

 riously ; branches opposite, nearly perpendicular to the stem, with a joint 

 immediately above their insertion ; cells oval, sessile, upwards of 10 times 

 the breadth of the stem, in pairs, at remote distances, projecting, and are 

 probably ultimately converted into branches ; sometimes they occur in pairs 

 or crowds in the axillae of the branches ; polypi extend considerably beyond 

 the margin, tentacula with hairs, which, by their motions, cause the water to 

 ascend in a current on one side, and descend on the other, acting, probably, 

 as aerating organs. 



197. V. Uva. — Stem creeping, irregularly branched, cells 



scattered. 



Grape coralline, Ellis, Cor. 27, t. xv. f. 25. D. — Sertularia uva, Linn. 



Syst. i. 1311 — S. acinacea, Pall. El. 123 Clytia uva, Lamour. Cor. 



Flex. 203. — On Flustra foliosa. 



Stein creeping, much waved, cells oval. This is a species, the true cha- 

 racters of which are involved in considerable obscurity. 



* Stem compound. 



198. V. spinosa. — Stem erect, dichotomously divided, waved ; 



cells on one side. 



Silk coralline, Ellis, Cor. 20. t. xi. f. 17- B — Sertularia spin. Linn. Syst. 

 i. 1312 — S. sericea, Pall. El. 114 — Laomedia spin. Lamour. Cor. Flex. 

 208 On oyster beds. 



Height upwards of a foot ; slender, like silk ; principal stem formed by 

 the union of several tubes, dichotomously divided ; subordinate branches al- 

 ternate, and dichotomously divided ; the cells seem confined to one side, ra- 

 ther distant, oval, sessile. 



Gen. LXXI. CYMODOCIA. Stem tubular, annulated 



below, united above, without any internal partitions ; cells 

 cylindrical, filiform, alternate or opposite. 



199- C. comata. Stem erect, branches verticillate and 



waved. 



Lamour. Zooph. 15, t. lxvii. f, 12, 13 — Coast of Devon, Dr Leach. 



Stem straight, cylindrical, slightly divided ; branches capillary, jointed, a 

 minute cell at each joint, with a wrinkled base. Structure yet obscure. 



At the close of this group of animals may be noticed the doubtful Sertula- 

 ria pustulosa of Ellis, Cor. 57, t. xxvii. £ B. It is described as jointed, and 

 alternately but thinly branched ; towards the upper part of every joint are 

 several shallow cells, having a little circular rim with a point in the middle 

 of each. Its relations remain to be determined. 



