328 Scientific Proceedings, Royal Dublin Society. 
delicate continuation of the polypary all over, and also a thin 
transparent layer of the gelatinous substance. Gonozooid not 
known. 
This species appears to be a very well defined one, possessing, 
as it does, a combination of characters which separates it from any 
other described form. Its closest allies are P. vestitus, All., and 
P. pailiatus, T. 8. Wright. The former, however, has the polyp- 
ary yellowish brown, with adherent particles of sand; there are 
no annulations at the base, and no gelatinous covering to the 
polypary: the gonophores, also, are only invested for about half 
their length by the polypary. P. gelatinosus agrees with P. pal- 
liatus in having the body of the polypite clothed up to the level of 
the mouth with a gelatinous envelope; but differs in the well- 
developed, ringed, occasionally much branched stems, and in the 
gonophores being borne on the stems, and not on the stolon. It 
is possible that when P. vestitus and P. palliatus have been redis- 
covered in any number in their original locality—the Firth of 
Forth—that then, as Mr. Hincks believes (‘‘ Brit. Hyd. Zooph.,” 
p. 95), they may be shown to belong to the same form, and then 
this present species may go along with them. It certainly pre- 
sents somewhat of a combination of the characters of the two. 
Until this is done, however, it seems best that it should remain 
separate, and rank as a distinct species. 
In one colony, obtained from the south-west of Ireland, the 
creeping stolon was so closely reticulated as to form an almost 
continuous chitinous crust on the shell on which it was growing. 
The species well illustrates the variability to which the different 
representatives of the genus Perigonimus are liable, and the danger 
of founding specific characters upon an individual colony. In the 
form represented in fig. 2 the stems are short, unbranched, and 
have the gelatinous envelope very thick. In the other form 
(fig. 3), from a different colony, the stems are much longer, more 
branched, and the gelatinous envelope only feebly developed. 
From careful comparison, however, and experience of a number 
of forms, I have no doubt but that they all belong to the same 
species. 
Habitat.—F rom rather deep water, growing on shells inhabited 
by Pagurus. Station 183, Dingle Bay; depth, 40 fathoms.— 
(R. D.8.): Log 738, south-west of Ireland; depth, 50 fathoms. 
