THE MICROPLANKTON OF PLYMOUTH SOUND. 163 
(2) Derogenes varicus (O. F. Miill.). Occurs in Sagitta bipunctata in the 
late cercaria stage in June. Jn old material of previous years it is 
quite common. 
(3) Turbellarian indet. Occurred occasionally in August and November. 
NEMATODA. 
Unidentified trematodes occurred occasionally free in the autumn and 
winter; a larval Ascaris (described in another paper of this 
Journal, p. 201) is common in Sagitta bipunctata. 
ANNELIDA. 
K: J. Allen, “ Polycheeta of Plymouth and the South. Devon Coast, ete.,” 
JMB. As OTS. 
The annelids with the exception of Tomopteris and Autolytus are all 
larval forms. 
(1) Autolytus longiferiens De St. Joseph. Occurred once at the end of 
January with eggs, twice with eggs at the beginning of September, 
and one male. 
(2) A. rubropunctatus (Grube). Once in September, 1915, twice in 
November, once in August and twice in September, 1916, always 
with eggs, 
(3) A. pictus (Ehlers). Once in September and once in Noversber, 1915. 
Once in September, 1916, alwavs with eggs. 
(4) A. sp. These were allied to A. Hdwarsi, a small species, three with 
eggs and one male, always in September. 
(5) Polynoé sp. juv. Once in December and once in the end of March. 
(6) Spionid larva, occasionally from November to March. Rarely in 
May and July. 
(7) Magelona sp. larva. Fairly common in July and August. 
8) Pecilochetus serpens Allen, larva. Occurred in small numbers 
} 
every month except December and April. Commonest in May 
and August. 
(9) Crrratulus sp. juv. Once only early m March. 
(10) Terebellid larva. Present every month, but not usually in large 
numbers except once in November, then rare till the end of 
February, when it increases and is very common in May. The 
houses of the very young larve are extremely pretty, the animal 
using all sorts of small organisms to cover itself, especially 
