130 
Z. HYDROIDA. 
Sertularia. 
teretiusculi, depressi, lineares, ssepe longissimi, tenuiter a scapo ori- 
untur, 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, clausa.” 
11 . s. tama in sca, cells opposite , tubular , the upper half di- 
vergent with a wide aperture sinuated on the margin ; vesicles 
oval , truncate , with two small points at the corners and a fabu- 
lous mouth . Ellis. 
Plate X. Fig. 2, 3, 4. 
Sea Tamarisk, Ellis, Corall. 4, no. 1, pi. 1, fig. a, A — — Sertularia tama- 
risca, Lin. Syst- 1307- Pall. Elench. 129. Ellis and Soland, Zooptu 
36- Berk. Syn. i. 216. Tart. Gmel. iv. 676. Turt. Brit. Faun. 212. 
Stew. Elem. ii. 441. Bose, Vers, iii. 106- Lamour. Cor. Flex. 188. 
Corallina, 82. Lam. Anim. s. Vert. 2de edit- ii. 153 Dynamena ta- 
marisca, Elem. Brit. Anim. 543. La D. tamarisque, Blainv . Acti- 
nol. 483. 
Hab. 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 Dean. 
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 are 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 subalternate , ovato - 
tubular , the mouth entire ; vesicles oval . 
Plate X. Fig. 1,1. 
Abies marina, Ger. emac. 1574, fig. Sibbald. Scot. ill. lib. quart. 55. 
