160 MARIE V. LEBOUR. 
(19) Citiarocyclis denticulata Fhr. Occasionally from Augus) to October. 
. J . . 1 
This species is abundent close to the shore. 
(20) C. edentata Brendt. Once oaly in October, water samoles. 
(21) Infusoria indet. Chiefly in the summer and early autumn in 
numbers. 
THE METAZOA. 
The Metazoa in the water samples being negligible the following is an 
account of the tow nettings examined as described above through the 
same period as the water samples and from the same locality. 
CQLENTERATA. 
The medusee are chiefly confined to the coarse and medium tow nets. 
Beginning at the end of January with Phialidium hemisphericum they 
continue for the rest of the year until nearly the end of November when 
they are absent for the winter. Ctenophores and Siphonophores repre- 
sented chiefly by Pleurobrachia pileus and Muggiea atlantica are common 
in the summer, although Pleurobrachia was not so numerous as usual this 
year, possibly owing to the April storms and the coldness of May and 
June. 
The medusee are specially interesting because they carry other animals 
parasitically and thus serve as effective transports. Those chiefly so 
utilised are Cosmetira pilosella, Phialidium hemisphericum, Obelia sp., 
Turris pileata and Stomotoca dinema ; perhaps the species most frequently 
so used, and necessarily so as they are the commonest, are Phialidium 
hemisphericum and Obelia sp. Phialidium serves as host for larval 
trematodes, larval pycnogonids and Jarval Peachia. Obelia has not been 
noticed as a host for Peachia larve, probably because it is too heavy to be 
‘arried by so small a medusa. Cosmetira serves as host for all three, 
Turris pileata and Stomotoca dinema for larval trematodes. The trema- 
todes are always the late cercaria stage of Pharyngora bacillaus (Molin), 
which reaches maturity in the mackerel (Lebour, J.M.B.A., 1915). This 
occupies the manubrium and mesogloea. It is interesting in this con- 
nexion that KE. T. Browne (P.Z.S., 1896) notes that a species of cercaria 
infects the mesoglea of Phialidium temporarium (i.e. P. hemisphericum) in 
Valencia Harbour, and that Halcampa (i.e. Peachia larva) also selected 
this medusa, attaching itself to the generative organs. I find that 
Halcampa attaches itself to the medusa margin as well as the inside 
of the generative organs. The pycnogonid Anaphia petiolata Kroyer 
lives in the larval state tightly folded up in the manubrium of 
Phialidium, Obelia and Cosmetira (Lebour, J.M.B.A., 1915). 
