105 



that part of the English channel formed by the Cornish 

 coast, it appears that this plain, translucent circumference 

 is the earliest visible process in the formation of new tubes. 

 But though thus liable to so many variations, it must not 

 be supposed that the species is to be with difficulty re- 

 cognized. It very rarely occurs that more than one varia- 

 tion is found in a single specimen ; and all the varieties 

 differ from a standard form; so that it is as easy to dis- 

 tinguished this as any other species. 



TRAILING CORAL. Tubulipora, (trahens, R. Q. C.) 

 Polypidom calcareous, creeping, adherent throughout, ir- 

 regularly and sparingly branched, narrow, with one or two 

 rows of tubes projecting from the upper surface. PI. xix., 

 fig. 3. 



Hub. On stones and shells from deep water, not un- 

 common ; Polperro. 



The polypidom varies -from a quarter to one inch in 

 length, but is very narrow and slender. It is adherent 

 throughout, trails over the surface of the stones or shells 

 on which it grows, and is tortuously, sparingly, and irre- 

 gularly branched. The tubes are commonly single, but 

 sometimes are in pairs, and project considerably, sometimes 

 in a straight and at others in a waved manner. When 

 the tubes, are in pairs they are always close together, but 

 each pair is separated from the next in the length ways 

 of the polypidom by an interval varying from one-eighth to 

 one-fifth of an inch in different specimens. Being unable 

 to refer this to any described species, I have provisionally- 

 given it the name of trahens as descriptive of its habit. 



SMALL PURPLE ESCHARA. T. Serpens. Polypidom 

 calcareous, purple or white; branches bifid, revolute ; 

 cells only on one side, long and tubular, in transverse 

 rows separated by a central groove. PI. xix., fig. 7. 



Small Purple Eschara, Ellis' Coral., p. 74, no. 6, pi. 27, 

 fig. e E. Millepora tubulosa, Ellis and Solander's Zooph., 

 p. 136, no. 11. jVlillepora liliacea, Turton's Lin., vol. 4, 

 p. 639. Tubipora serpens, Turton's Lin., vol. 4, p. G14. 

 Stewart's Elem., vol. 2, p. 426. Millepora tubulosa, Stew- 

 art's Elem., vol. 2, p. 428. Tubulipora serpens, Fleming's 

 Brit. An., p. 529. Johnston's Brit. Zooph., p. 268, pi. xxx., 

 figs. 4 aud 6. 



Hab. On stones, shells, corallines, and sponges, common 

 at all distances. A*. Q. C. Pallas. 



This species is common at all seasons, and is generally 

 parasitical on the horny corallines, more particularly on ihe 



