Abstract of Memoir 
RECORDING WORK DONE AT :THE PLYMOUTH LABORATORY. 
The Development of Alcyonium Digitatum, with some notes on the Early 
Colony Formation. By Annie Matthews, M.Sc. 
Quart. Journ. Micr. Sci., Vol. 62, Part 1, New Series, 1916. 
THE above paper is a record of the successful rearmg of Alcyonium 
larve in tanks at the Plymouth Laboratory. 
Ripe male and female specimens collected near the Eddystone during 
the breeding seasons of 1912-13 and 1913-14 spawned in the tank water, 
and fertilised eggs were collected from which eventually young colonies 
were obtained. 
Segmentation gave rise in various ways to a morula, followed by the 
pre-planula and planula stages. The pear-shaped free-swimming planula 
eventually settled by the broad anterior end, and the mouth arose at 
the narrow posterior end subsequent toa general flattening of the settled 
planula along the long axis. 
The characteristic eight mesenteries grew out into the ccelenteron on 
the second day of fixation, followed by the appearance of spicules and 
eight hollow circumoral tentacles which alternated in position with the 
mesenteries. ree entrance of food was permitted on the fourth day, 
after the degeneration of the base of the cesophageal invagination. On 
the fifth and sixth day of fixation respectively the ventral and dorsal 
mesenteric filaments were formed, the two being of homogeneous origin, 
i.e. consisting of endodermic and ectodermic portions developed in 
different degrees. 
At the end of the third week the first bud grew as an outgrowth from 
the basal stolon formed by the solitary polyp. 
Very young fixed stages were fed with fine plankton, but colonies of 
two or three individuals or more were successfully fed on larve and 
single adults from Leptoclinum and Botryllus colonies. The early buds 
are arranged in circles round the parent, but in colonies of thirty-two 
individuals budding took place irregularly. 
A. M. 
——s ee 
