Cristatella, 
Z. ASCIDIOIDA, 
311 
are known to undergo somewhat similar changes. The eggs float 
in the water from their lesser specific gravity, but often they be- 
come attached by their spines to the filaments of confervse, &c. where 
they float until the young are hatched and afford to them an im- 
mediate place of rest. 
M. Turpin has ascertained that some varieties of silex contain im- 
mense numbers of the ova of the Cristatella and Alcyonella, preserv- 
ed in entire perfection. Ann. des Sc. Nat. Part. Zool. vii. 120, 
plates 6 and 7. 
43. Alcyonella,* Lamarck. 
Character. Polypidom fixea f, incrusting , or floating , in 
the form of an irregular sponge-like mass composed of vertical 
aggregated membranaceous tubes opening on the surface . — Poly- 
pes ascidian , the mouth encircled with a single series of filiform 
tentacula depressed or incomplete on one side : eggs coriaceous , 
smooth. 
1. A. STAGNORUM. 
Plate xliv. 
Variation Sponge-like, massive -Alcyonium fluviatile, Bose, Vers, iii. 
159. Corail. 250. Ephydatia Gibbsii, Gray, Brit. PI. i. 353 
Alcyonella stagnorum, Lam. Anim. s. Vert. ii. 102. 2de edit. ii. 116. 
Stark, Elem. ii. 442. Lamour. Soland. tab. 76, fig. 5 — 8. (bad.) Teale 
in Trans. Leeds Phil, and Lit. Soc. i. 116, pi. 12, and in Mag. Zool. 
and Bot. i. 293 A. fluviatilis, Raspail in Mem. de la Soc. d’Hist. 
Nat. de Paris, iv. 130, pi. 12 — 16. L’ Alcyonella des etangs, Blainv. 
Actinolog. 491, pi. 85. fig. 8. 
Variation Polypidom lotted or stellate — Polypes a panache, Tremb. Mem. 
210, pi. 10, fig. 8 — 9. Reaum. Mem. des Insect, vi. pref. lxxvi. The 
Bell-Flower- Animal or plumed Polype, Baker, Employ. Micros. 306, pi. 
12, fig. 15 — 22 Hydra campanulata, Lin. Syst. edit. 10, 817 
Tubularia crystallina, Pall. Elench. 85.- T. campanulata, Lin. Syst. 
1303. Berk. Syn. i- 215. Shaw Nat. Misc. x. pi. 354. Turt. Gmel. iv. 
668. Turt. Brit. Faun. 211. Adams on the Microscope, 449, pi. 22, 
fig. 32. Bose, Vers, iii. 92. Blumenb. Man. 272 T. rep tans, Bose, 
Vers, iii. 93. Plumatella cristata, Lam. Anim. s. Vert. ii. 107. 2de 
edit. ii. 122. Stark, Elem. ii, 441. Blainv. Actinol. 490. PI. campa- 
nulata, Risso, L’Europ. Merid. v. 308.- Naisa reptans, Corall. 99, 
pi. 6, fig. 4. Cristatella campanulata, Flem. Brit. Anim. 518. 
C. paludosa, Daly ell in Rep. Brit. Assoc, an. 1834, 606. 
Hab. Stagnant waters, especially in such as are tinctured with iron 
* A diminutive from Halcyon. The sponge -genus Alcyonellum of Quoy and 
Gaymard, being of subsequent creation, cannot be retained. 
