ZOOPHYTES. 
31 
on the gonothecae. It sometimes occurs on Stenorhynchus 
rostratus between tide-marks. 
Plumularia Gatharina , Johnst.; Hincks, Brit. H. Z. 
vol. i. p. 299. 
Common on Ascidians, tubes of Thelepus , and the roots of 
other corallines in deep water. 
Plumularia frutescens, Ellis & Solander; Hincks, Brit. H. Z. 
vol. i. p. 307. 
Occasionally thrown on the West Sands after storms, and 
also brought in by the deep-sea lines of the fishermen. The 
smaller specimens are pale. One example is 6 inches in 
height, and broadly branched. 
Order Medusid^e. 
The Medusidee abound chiefly in autumn in the bay, the 
most conspicuous amongst the larger forms being Aurelia and 
Cyanea : the former often occurring in such numbers as to form 
a closely packed layer on the surface of the sea over considerable 
areas; and though not in the dense party-coloured masses of 
various species occasionally seen in the Hebrides, still they form 
an interesting feature. At certain points the bay in quiet 
weather is quite purplish with thousands, many of which are 
loaded with ova; and through the transparent umbrellas the 
abdominal feet of the parasitic Hyperidse are observed in con¬ 
stant vibration. Occasionally, whether from accident or de¬ 
sign, one specimen is found adhering to the umbrella of another, 
and is thus carried through the water. Moreover, on many of 
the stones at the East and West Bocks, near low-water mark, 
a u Hydra tuba ” is found, which maybe the hydroid condition 
of the foregoing. This pretty little white structure, developed 
from the ova of Aurelia and its allies, can be observed in all 
stages not only throwing out lateral buds like a Hydra , but 
by transverse fission dividing into a series of saucer-shaped 
bodies which ultimately assume the form of the adult Aurelia. 
This form, it is well known, formed the subject of valuable 
observations by the late Prof. M. Sars, and afterwards, amongst 
