DurErpen—Wotes on the Hydroida and Polyzoa. 327 
annulations, and a less amount of the gelatinous and foreign 
encrusting matter. ‘The gonophores show a distinct delicate con- 
tinuation of the polypary over them. In the great amount of 
branching, and also in the ringed origin of the stems, this form 
varies from the description given of P. repens ; but these characters 
I regard as insufficient to establish a specific distinction. 
A colony of this form was obtained growing luxuriantly on a 
Scaphander from Galway Bay, from a depth of 15 fathoms, and 
another colony from off the Skelligs, at a depth of from 40 to 80 
fathoms. Collections from Dingle Bay also yielded this more 
branching form with the stems annulated at their origin. 
From Bantry Bay I received a colony of the form resembling 
the one which Mr. Alder regards as the young stage of P. repens 
(“Brit. Hyd. Zooph.,” fol. 17). It was growing upon a crab. 
The stems are quite short compared with the examples described 
above. One interesting feature in these is, that within the gastric 
cavity of many of the polypites a nematode is present. I have 
found this relationship in quite a number of cases, both in 
specimens of Perigonimus and of Bougainvillia. It appears as if 
the nematode were capable of making its exit, as I have found 
them projecting some distance beyond the mouth of the polyp- 
ite, and in other cases quite free amongst the branches. It is 
evidently a condition of partial parasitism. 
Perigonimus gelatinosus, 0. sp. 
(Pl. XIV., figs. 2 and 3.) 
Stems short and simple, or longer, and with a few branches; 
polypary yellowish, gradually thinning above, and greatly ex- 
panded to form a thin covering for the polypites; nine or ten dis- 
tinct annulations at the origin of the stems; somewhat wrinkled; 
covered on the outside with a gelatinous envelope, developed 
to a greater or less extent with foreign particles embedded in 
it, and extending so as to completely enclose the contracted 
polypites. Polypites, with a conical proboscis, in contraction 
strongly fusiform or nearly spherical; tentacles about eight. 
Gonophores numerous, produced on the stems, borne on long 
peduncles, often slightly ringed at irregular intervals, and with a 
