105 
l hat part of the English channel formed by the Cornish 
?°ast, it appears that this plain, translucent circumference 
ls the earliest visible process in the formation of new tubes. 
Rut though thus liable to so many variations, it must not 
“ e supposed that the species is to be with difficulty re- 
cognized. It very rarely occurs that more than one varia- 
nce is found in a single specimen ; and all the varieties 
'ttffer from a standard form; so that it is as easy to dis- 
^"gnished this as any other species. 
^RAILING 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. 1 1. xix., 
% 3. 
Rub. On stones and shells from deep water, not un- 
c °tnmon ; Polperro. 
. The polypidom varies from a quarter to one inch in 
e Dgth, but is very narrow and slender. It is adherent 
throughout, trails over the surface of the stones or shells 
° ri which it grows, and is tortuously, sparingly, and irre- 
gularly branched. The tubes are commonly single, but 
?°inetimes are in pairs, and project considerably, sometimes 
la a straight and at others in a waved manner. When 
the lubes, are in pairs they are always close together, but 
e<ic h pair is separated from the next in the length ways 
the polypidom by an interval varying from one-eighth to 
' iae -li(th of an inch in different specimens. Being unable 
C refer this to any described species, I have provisionally 
h ,y en it the name of trahens as descriptive of its habit. 
S ^ALL PURPLE ESCHARA. T. Serpens. Polypidom 
Ci *lcareous, purple or white j branches bifid, revolute , 
cells only on one side, long and tubular, in transverse 
r °'vs separated by a central groove. PI. xix., fig. 7. 
R Small Purple Eschara, Ellis’ Coral., p. 74, no. 6, pi. 27, 
h S- e E. Millepora tubulosa, Ellis and Solander’s Zooph., 
136, no. 11. Millepora liliacea, Turton’s Lin., vol. 4, 
639. Tubipora serpens, Turtons Lin., vol. 4, p. 614. 
'“'’Wart’s Elem., vol. 2, p. 426. Millepora tubulosa, Stew- 
?. n > Elem., vol. 2, p. 428- Tubulipora serpens, Fleming’s 
g r *f- An., p. 529. Johnston’s Brit. Zooph., p. 268, pi. xxx., 
4 and 6. 
at #«6. On stones, shells, corallines, and sponges, common 
distances. R. Q. C. Pallas. 
4- his species is common at all seasons, and is generally 
Har| *sitical on the horny corallines, more particularly on the 
