632 Cc. H. MARTIN. 
bud externally, but were not in a position to positively affirm 
this statement. 
They describe and figure two forms of ciliated embryos, a 
large and a small, but as in each case the buds were freed 
from the parent by pressure they were never able to follow 
their development into the fixed form. 
In 1859 Strethill Wright described shortly under the name 
of Corethra sertulariz the species at present known as 
Ophryodendron sertularizx. In two further short papers 
he identified his form wrongly with the Ophryodendron 
abietinum described by Claparéde and Lachmann, and 
added some further details on the movements of the animal. 
Strethill Wright was at first inclined to regard the vermi- 
form individuals as Gregarime Parasites, but im his later 
paper he considered that they were probably gemme. He 
also figures in his paper in the ‘ Annals and Magazine of 
Natural History’ for 1861, the ciliate embryo, which he 
“freed from the parent form by a somewhat troublesome 
] 
midwifery,” and described very fully the movements of the 
proboscis. 
In 1875 Hincks published some observations on Ophryo- 
dendron abietinum, and on a new species O phryoden- 
dron pedicellatum. He was the first observer to point 
out clearly that Ophryodendron is a dimorphic form, and 
that (p. 4) the vermiform individual cannot be regarded as a 
proboscidiform individual with a retracted proboscis. He 
says (p. 8), “If my view of the history then be correct, the 
Ophryodendron is a dimorphic animal, that which may be 
called the primary zooid giving origin by gemmation to 
bodies unlike itself which, on becoming free, group them- 
selves around the parent organism and lead with it an asso- 
ciated life.’ Hincks failed to see the ciliated embryo, and 
could find no trace of any corpuscle resembling the thread 
cells of the hydroid even in Ophryodendron abietinum. 
In 1876 von Koch published a paper on a supposed new 
species, Ophryodendron pedunculatum, which he found 
on Plumularia from Messina. (This species is probably 
