EUCRATIAD.E: HIPPOTHOA. 291 



the Vorticellae ; but the conjecture has been shewn to be groundless 

 by Mr. Lister's discovery of its polypes, which are truly ascidian, 

 and nearly allied to those of the Flustra. 



10. HIPPOTHOA,* Lamouroux. 



CHARACTER. Polypidom confervoid, adherent and creeping, 

 calcareous, irregularly branched, the branches frequently anas- 

 tomosing, formed of elliptical cells linked to each other at the 

 extremities ; aperture lateral, near the distal end. Polypes 

 ascidian. 



1. H. CATENULARIA, cells contiguous, ovate, thick, with a 

 large oblique oval aperture. Prof. Jameson. 



PLATE L. FIG. 9, 10. 



Tubipora catenularia, Jameson in Wern. Mem. i. 561. Tubipora catenulata, Stetv. 

 Elem. ii. 425. Hippothoa catenularia, Flem. Brit. Anim. 534. Hassall in Ann. 

 and Mag. Nat. Hist. vi. 170. Couch Zooph. Cornw. 43 : Corn. Faun. iii. 101, 

 pi. 18, fig. 5. Hippothoa Elliotae, Gray Zool. Misc. 34. 



Hah. On shells, especially bivalves, in deep water, not un- 

 common. 



Polypidom closely adherent, much and irregularly branched in a 

 confervoid manner, white, smooth, glossy, calcareous, the branches 

 spreading, frequently anastomosing, sometimes parallel and coales- 

 cing, formed of a series of cells connected like a string of bugles ; 

 cells oval, widest and rounded anteally, the aperture oval with a 

 plain thickish rim, placed near the top. In its mode of ramifica- 

 tion this coralline resembles many of the plant-like figures in 

 marble or agate. " The branches proceed nearly at right angles, 

 issuing from the margin beside the mouth," and will spread, on a 

 favourable site, to such an extent as will cover an inch or two 

 square surface. When alive it "appears like dew drops, and is 

 easily separated from the shell by a pin ; but is strongly attached 

 when dry." Gray. In this state the aperture of the cells is some- 

 times closed by a membrane. The polype remains undescribed. 



2. H. DIVARICATA, cells remote, ovate-lanceolate or fusiform, 

 the aperture small and round. Miss Elliott. 



* A Nereid : Hesiod. Theog. 251. 



' liriroOorj T' epotffffa, KUI 'Iirirovot) poSoTrrixvc. 

 The charming Hippothoa and rosy-armed Hipponoe. 



The genus TEREBRIPORA of D'Orbigny appears to be synonymous with Hippothon. 



u2 



