NOTES-ORIGINAL AND SELECTED. I43 
week in May, the animals died off rapidly, and with the de¬ 
composition of the body the eggs were liberated. The writer 
has noticed that isolated individuals containing large numbers 
of eggs never deposit them while alive. The algal cells set 
free on the death of the worm continued to live, and 
developed an investing membrane and passed into a resting 
stage, probably awaiting an opportunity of invading the next 
generation of Dalyellia. 
Prof. Sekera thinks that the alga is of little or no value to 
the worm by way of providing food, his reasons being that closely 
allied species living under similar conditions do not contain 
algae, and that solid food is ingested after the algal cells are 
fully developed. 
Sir J. G. Dalyell wrote an account of this interesting species 
in 1814, and states that it sometimes occurs in large numbers, 
and then disappears suddenly. He found his specimens chiefly 
in the spring, but some were found in autumn. 
Von Graff in his Monograph on the Turbellaria gives a list of 
24 species living in fresh water which are frequently associated 
with algal cells. 
An interesting description of the association of algal cells 
with a marine Turbellarian worm (Convoluta roscoffiensis ) is 
given by Iveeble in his little book on Plant Animals. In this 
case, however, true symbiosis is undoubted, as the animal ab¬ 
stains from solid food when in an adult state, and digests the 
products assimilated by the alga.—H. Whitehead, B.Sc., 
Essex Museum of Natural History, Stratford. 
BOTANY. 
Lathyrus tuberosus L. at Buckhurst Hill.—The Fyfield 
Pea has appeared during the last two summers as a “ casual ” 
upon the railway embankment of the loop line between Woodford 
and Chigwell, in the parish of Buckhurst Hill, between there 
and the river Roding. Several plants, covering a square yard of 
surface, and possibly all originated from a single tuber, were 
found by Mr. Howard growing amongst the clinker ballast thrown 
down upon the embankment, and an unmistakable specimen 
was (September 1912) brought to me for specific confirmation. 
The railway embankment in question has proved a rich ground 
for “ casuals ” for years past, but the present record, by which 
