Sertularia. 
Z. HYDROIDA. 
121 
articulated, cylindrical or somewhat dilated at the aperture. Vesicles 
numerous, scattered or imperfectly clustered, large and shaped some- 
what like the flower of a Calceolaria, with a short tubulous aperture 
in the middle of its concavity, which is on the superior and inner as- 
pect. 
I have named this curious and very interesting species after its 
discoverer, to whose kindness I am indebted for the specimen that fur- 
nished our figure and description. In habit and structure it closely 
resembles Th. halecina, from which it is, however, at once distin- 
guished by its remarkable ovaries. 
3. T. muricata, vesicles roundish or ovate , echinated. Dr 
David Skene. 
Plate VII. Fig. 3, 4. 
Sertularia muricata, Ellis and Soland. Zooph. 59, pi. 7, fig. 3, 4. Turt. 
Gmel. iv. 681. Turt. Brit. Faun. 215. Stew. Elem. ii. 445. Jame- 
son in Wern. Mem. i. 564. Flem. Brit. Anim. 543. Hogg's Stockton, 
34. Bose, Vers, iii. 115. Laomedea muricata, Lamour. Cor. Flex* 
209. Corallina, 92 La Sertulaire muriquee, Blainv. Actinol. 480. 
La Campanulaire muriquee. Ibid. 473. 
Hab. On old shells in deep water. The sea at Aberdeen, Skene . 
Frith of Forth, Jameson. Seaton, J. Hogg. Near Scarborough, 
W. Bean. 
Polypidom from 2 to 4 inches high, rooted by a fibrous entangled 
mass, irregularly branched, stout and rigid, yellowish-brown ; the 
stem and branches composed of capillary tortuous tubes closely ag- 
glutinated, but the extremities of some of them become free and ap- 
pear like simple fibres ; branches erecto-patent, slightly tapered at 
the point. Cells visible only on the simple fibres, small, alternate, 
separated by an oblique joint, sessile, campanulate, with an entire 
even aperture. Vesicles very numerous and often crowded, shortly 
stalked, roundish or ovate, somewhat compressed, and rough with 
prickles arranged in lines on elevated striae : when filled with ova the 
centre is of a deep chesnut-brown colour. 
May not the obscure Sertularia echinata of Linnaeus be re- 
ferable to this species ? 
6. Sertularia,* Linnaeus. 
Character. Polypidoms rooted , plant-like , variously branch- 
ed, the divisions or branches formed of a single tube divided, at 
regular intervals by imperfect septa : cells paired or arranged in 
From sertula, the diminutive of serta, a garland. 
