TUBULIPORA. ae 
tata ; at times, however, on stones and shells from deep 
water. It is occasionally cupped, but more generally it is 
shallow, like a saucer. Its largest size is about half an 
inch; with us it is less. It is calcareous and snow-white. 
The margin is plain and entire. The series of tubes or 
cells nearest the margin have plain angular apertures, like a 
honey-comb. The inner cells are tubular, and in rows. 
2. TUBULIPORA HISPIDA, Cordiner. 
Hab. Parasitical on Flustre and other seaweeds; also 
on shells and rocks. With us, on the west coast of Scot- 
land, 7. hispida, in its common form, is far from being 
rare, and it is got most frequently on Delesseria sanguinea ; 
but larger and finer specimens are found, at times, on the 
roots of the large tangle and on shells from the deep. The 
broadest specimens I have met with were on Pinna ingens, 
from the island of Tiree. I have a special regard for this 
little zoophyte, as it gave rise to what has been, to me, a 
very pleasant and profitable correspondence with my excel- 
lent friend, Dr. George Johnston, the well-known author of 
the ‘ History of British Zoophytes,’ and many other valuable 
works on different branches of Natural Science. When he 
was preparing his first edition of the ‘ History of Zoophytes,’ 
he wrote to me, saying, that he had observed, in my ‘ New 
