748 Proceedings of Royal Society of Edinburgh. [sess. 
HYDRO MEDUSAE. 
Order — Anthomedus^. 
Corymorpha nutans, Sars. (Tables I. 11 ; II. 14.) 
Steenstrupia rubra , Forbes, 1848, p. 73, pi. xiii. 
Corymorpha nutans , Allman, 1872, p. 388, pi. xix. 
Browne, 1896, p. 463, pi. xvi. 
In 1901 and 1902, it appeared about the end of May, and dis- 
appeared about the middle of July. It was most plentiful during 
the early part of June, when both young and adult stages were 
present. 
At Plymouth and Valencia Island this medusa usually appears 
about the end of March or early in April, reaches maturity early 
in May, and disappears during the summer. 
The hydroid Corymorpha nutans has not yet been recorded for 
the Clyde. 
Cytseandra areolata, Haeckel. (Tables I. 5 ; II. 6.) 
Cytceandra areolata , Browne, 1898, p. 817, pi. xlviii. 
In 1901, a few specimens were taken during April and July. 
In 1902, it was taken from March to July. It was generally 
very scarce, but was more plentiful in May than in the other 
months. Young stages occurred in March and the beginning 
of April. Adults were present in May. 
Ectopleura dumortieri (van Beneden). (Table I. 27.) 
Edopleura dumortieri , Hincks, 1868, p. 124, pi. xxi. 
In 1901, a single specimen was taken on 15th October, and 
another on 18th October. Both were adult males. 
Description of the adult medusa : — The umbrella is somewhat 
conical, a little longer than broad, with an inverted margin 
and fairly thick walls. Upon the ex-umbrella there are eight 
longitudinal rows of nematocysts, extending from the basal 
bulbs of the tentacles (two rows from each bulb) to near the 
top of the umbrella. The nematocysts are more numerous in 
each row near the margin of the umbrella than near the 
