i. 
found on the Coast of Northumberland. 313 
Atractylis arenosa, n.sp. Pl. XIII. figs. 5-7. 
Polypary minute, consisting of a creeping fibre, from which 
arise short funnel-shaped tubes, rather irregular in form, but 
always expanding more or less at the top, from which the polypes 
issue ; generally covered with minute grains of sand. Polypes 
entirely retractile, with long, slender, strongly muricated tenta- 
¢les, varying in number, according to age, from six to twelve. 
- The genus Afractylis has been established by Dr. Strethill 
Wright for a group of Hydroid Zoophytes resembling Euden- 
drium in many of their characters, but differing in the conical 
form of the mouth of the polype, and its retractility (partial 
or complete) within the tubular polypary. They are generally 
of small size, and seldom branched. Their reproduction is usu- 
ally by medusoids; but Dr. Wright, who has lately met with the 
present species in the Firth of Forth, has ascertained that it 
produces planuloid young direct from the summit of the ovarian 
sac. This affords another proof of the difficulty of establishing 
_ a genus from the mode of development. 
I have met with this species occasionally, for some years past, 
on stones and the roots of Laminaria at Cullercoats and Tyne- 
mouth. From its minute size, it requires to be carefully looked for. 
Atractylis linearis, n. sp. Pl. XIV. figs. 1-3. 
Polypary linear, horn-coloured, unbranched (?), nearly smooth, 
a little undulating and slightly wrinkled on the lower part; the 
stems united together by reticulated creeping tubes at the base. 
Polypes slender, retractile, with eight long muricated tentacles, 
held alternately up and down. Gonophores pear-shaped or sub- 
globular, set two or three together on the stem of the polypary, 
each capsule containing a single medusoid. Height a quarter 
of an inch. 
_ Medusoid globose, slightly truncated below, with a contracted 
aperture; four moderate-sized subclavate tentacles arise from 
four semicircular yellowish lobes at the margin of the umbrella: 
sub-umbrella small, with four radiating canals, the centre occu» 
pied by a mass of yellowish or orange granules, apparently ova; 
peduncle inconspicuous, branched at the base. 
On Turritella communis, Astarte Damnonia, and other shells 
from deep water, Cullercoats, 
. This species has considerable resemblance to 4. repens, Wright, 
but its polypary rises much higher, is proportionally more slen- 
der, and not so much expanded at the aperture. In the young 
state, however, it is difficult to distinguish them. Their medu- 
soids, nevertheless, are very different, and prove them to be 
distinct species. I have never met with A. linearis branched, 
though it is possible it may occasionally be so in luxuriant 
specimens. 
