Gatty Marine Laboratory, St. Andrews. 127 
of the series, which follows the same backward slope as the 
others, to represent them, though this is unlikely. He 
describes and figures a bud, and compares it with budding 
in the Turbellarians and Naidz. On the whole, there are 
no reliable grounds for separating this form from /’, implexa. 
Dalyell * (1853) gave a graphic account of the external 
features of the annelid and its mass of tubes, which, he 
correctly stated, was ‘‘ penetrated by numerous deep cavities 
of indeterminable size and form.’ He also found the 
greyish annelids of unequal size, but he did not notice 
buds. 
Huxley ¢ in 1855 furnished a careful account of the 
southern type which he termed Protula dysteri, its distin- 
guishing features being its “ fissiparous multiplication ” and 
its hermaphrodite condition. He described the branchize 
and their green blood-vessels; the alimentary canal with its 
crop, stomach, and intestine ; the ‘‘ vascular” system, which 
he did not consider equivalent to that of higher forms, the 
ceelomic fluid representing it ; the nervous system, repro- 
ductive elements, sete, and uncini; and concluded by a 
digest on fissiparous multiplication, He describes a ciliated 
canal running along the ventral surface of the intestine and 
apparently opening at the anus, but such probably was a 
misapprehension, He did not discriminate the differences 
in the structure and distribution of the bristles, yet the 
general account is worthy of the distinguished author, who, 
however, considered in 1865 that his form was probably 
identical with the northern type which had previously been 
described by Sars. 
Keferstein { (1862) found the same form at St. Vaast 
with free-swimming young. His figures of the bristle and 
hooks are insufficient for identification, though they apply 
to the common form. 
Claparede § in 1863 procured Pretula dysteri off the shores 
of France, and gave a detailed description of it. He likens 
the expanded branchial apparatus of the annelid to the 
lophophore of a Polyzoon, His examples had two eyes and 
occasionally other black specks. In the main his account 
agrees with that of Huxley, though he points out and figures 
the enlargements at the tips of the branchial filaments not 
mentioned by the English author. These enlargements, 
* Powers Creat. ii. p. 250, pl. xxxiv. figs. 1-6. 
+ Edin. New Philos. Jour, vol. i. n. 8. p. 113, pl. i. figs. 1-11. 
} Zeitsch. f. w. Zool. Bd. xii. p. 128, pl. xi. figs. 28 & 24 (1862). 
§ Beobach, Anat. u. Entwicklungs. Wirb. Thiere, p. 31, Taf. xy. 
figs. 16-22. 
