British Hydrozoa, Actinozoa, and Polyzoa. 83 
the body, filiform tentacula are scattered. The gonophores are 
in the form of mulberry-like masses, at first sight apparently 
sessile, but really upon very short gonoblastidia, which are 
situated in openings in the creeping base of the hydrozoon. 
Tubiclava Cornucopia was dredged in from 80 to 100 fathoms, 
about twenty miles north of Unst in Shetland, and was parasitic 
on the shells of Astarte sulcata and Dentalium Entalis. It is 
worthy of remark, that in every instance the hydrozoon was ob- 
served upon shells still occupied by the living Mollusca, and 
that it invariably had assumed a position at the posterior ex- 
tremity of the shell, where it would receive the benefit of the 
aqueous currents caused by the mollusk, which, while providing 
for its own necessities, thus unwittingly performed the kindly 
office of feeding its hungry neighbour. 
The genus in which this undescribed form is placed was esta- 
blished by Professor Allman in the ‘ Report of the British Asso- 
ciation’ for 1862. 
Fam. Tubulariade. 
Genus EupENprium (Ehrenberg). 
Eudendrium annulatum, n. sp. Pl. IX. figs. 1-3. 
E£. fruticosum ; ramis majoribus crassis, coalescentium fistularum 
insolito reticulo obductis ; ramulis numerosissimis, brevibus, passim 
distincte (sicut in Coryne ramosa) annulatis ; polypis calices non 
expansos obsidentibus, tentaculis 16-20 preeditis; gonophoris 
uvarum formam simulantibus, in gonoblastidiis positis. 
Hydrozoon quatuor pollices attingit. In freti “ Burrafirth” cavernis 
apud insulas Zetlandicas vitam degit. 
This Eudendrium grows to a height of about 4 inches, and is 
seen at a glance to differ from its congeners EZ. rameum and E. 
ramosum in its more shrubby and dense habit. The main stems 
are very thick and strengthened with a curious network of ana- 
stomosing tubes on their surface (Pl. IX. fig. 3). The smaller 
branches are closely and regularly ringed in every part (fig. 2), 
and are excessively numerous. The tubes are not expanded at 
their extremities to receive the polypites, as is the case in some 
allied species. The polypites are furnished with from sixteen to 
twenty tentacles. The gonophores are grouped in clusters, 
consisting of eight to twenty egg-shaped bodies attached round 
the axis of gonoblastidia, which are of moderate length. 
Eudendrium is a difficult genus ; but the present species appears 
to be very distinct from the seven British forms which have 
hitherto been described. It was found in a cave, known as 
“‘Buness Hall,” which is one of many caverns, all remarkably 
rich in animal life, which penetrate the cliffs on the eastern side 
of Burrafirth, the northernmost of the voes of Shetland. It was 
6* 
