130 Z. HYDROIDA. Sertularia. 



teretiuscuH, depress!, lineaves, saepe longissimi, tenuiter a scapo ori- 

 iintur, bifariam serrulati denticulis, uti ipse quoque scapus s. rhachis. 

 Denticuli (sic potius in hac specie vocandi) subtubulosi, exigui, sim- 

 plices. Ovaria ab altero stirpis latere in ramulis crebra, secunda, 

 parallela, versus rami extremitatem sensim minora, membranacea, 

 stirpi concoloria, obovato-subquadrangula, clan§a." 



11. S. TAMARiscA, cells opposite^ tubular, the upper half di- 

 vergent ivith a wide aperture sinuaied on the margin ; vesicles 

 oval, truncate, loith ttvo small points at the corners and a tuhu- 

 lous mouth. Ellis. 



Plate X. Fig. 2, 3, 4. 



Sea Tamarisk, Ellis, Corall. 4, no. 1, pL 1, fig. a, A Sertularia tama- 



risca, Lin. Syst. 1307- Pall. Elencli. 129- Ellis and Soland, Zooph. 

 36. Berk. Syn. i. 216- Tiirt Gmel. iv. 676. Turt. Brir. Faun. 212. 

 Stein. Elem. ii. 441. Bosc, Vers, iii. 106. Lamoiir. Cor. Flex. 188. 



Corallina, 82. Lam. Anim. s. Vert. 2de edit. ii. 133 Dynamena ta- ^ 



marisca, Flem. Brit. Anim. 543 La D. tamarisque, Blainv. Acti- 



nol. 483. 

 Hah. On old shells in deep water, not common. Near the island 

 of Dalkey, t the entrance of the harbour of Dublin, Ellis. Near 

 Aberdeen, Dr David Skene. Frith of Forth, Dr Coldstream. Very- 

 rare at Scarborough, Mr Bean. 



Polypidom from four inches to " sometimes nearly a foot" in height, 

 rooted by a creeping vermicular fibre, stout and erect, denticulated 

 throughout, bifariously branched, the branches alternate, rather dis- 

 tant, either simple or semipennated with secondary shoots, for these 

 appear only to spring from the upper side of the branch, and are erect. 

 The cells ai'e of a thin transparent corneous texture, large, smooth, 

 exactly opposite, in approximated pairs, the upper half free and di- 

 vergent, and the margin of the aperture obsoletely tridentate. Ve- 

 sicles large, unilateral, scattered, obcordate or pyriform with a tubu- 

 lar aperture. It seems that the little spine on each side is dependant 

 on the age of the vesicle, and not perceptible when this is young. 

 When mature it is filled with orange-coloured ova — In the thin tex- 

 ture of the polypidom generally, and in the form of its cells, this spe- 

 cies resembles Sert. rosacea ; but its robust habit, and the manner 

 of its branching, give it at least equal claims to affinity with the fol- 

 lowing. 



12. S. ABiETiNA, cells nearly opposite or suhaltemate, ovato- 

 tuhular, the mouth entire ; vesicles oval. 



Plate X. Fig. 1, 1. 

 Abies marina, Ger. emac. 1374, fig. Sibbald. Scot. ill. lib. quart. 55 



