12 Prof. Allman on the Hydroida. 



Perigonymus Muscus, mihi. 



Zoophyte consisting of numerous erect stems, about half an 

 inch in height, not composed of coalesced tubes, springing at in- 

 tervals from a creeping stolon, and sending off short branches, 

 which are themselves for the most part without further ramifica- 

 tion; polypary light brown, slightly corrugated, and with a 

 well-marked cup-like dilatation at the base of the polype. Po- 

 lypes semi-retractile, light reddish-brown, with about sixteen 

 tentacula directed, in extension, alternately backwards and for- 

 wards. 



Gonophores medusiferous, borne upon a rather long peduncle, 

 and springing from the branches at a short distance behind the 

 polype. Medusoid dome-shaped, with the four radiating canals 

 terminating below, each in a large reddish bulb, which sends off 

 two very extensile filiform tentacula, having an ocellus at the 

 base of each; manubrium extending to about a third of the 

 entire depth of the umbrella, and with four short oral tentacula. 

 The medusoid is thus in all points undistinguishable from that 

 of Perigonymus ramosus, Van Beneden. 



In a rock-pool, Torquay, where it occurred abundantly, creep- 

 ing over the bottom in small moss-like tufts. 



The small size and general habit of the present species, its 

 more simple ramification, and the fact that its stems consist of 

 a single tube, instead of being composed of numerous tubes 

 coalesced into a dense bundle, at once separate it from P. ramosus, 

 Van Beneden, notwithstanding the fact that the medusoids of 

 the two species are indistinguishable. 



Tuhularia Bellis, mihi. 



Basal portion of coznosarc prostrate, creeping, and sending up 

 short, free, sparingly branched stems, which rise to f inch or 

 1 inch in height; polypary, where it covers the lower part of the 

 upright stems, and the whole of the prostrate portion, marked 

 by wide but distinct annulations ; ccenosarc orange, deepening 

 in tint towards the base, expanding into a collar immediately 

 below the polypes. Polypes measuring, in full-sized specimens, 

 about 5 lines from tip to tip of the extended tentacula; body 

 of polype scarlet. 



Gonophores borne upon short, erect, branched peduncles ; 

 each gonophore with four well-marked tentaculoid tubercles on 

 its summit ; peduncles and spadix scai'let. 



A beautiful little Zoophyte, conspicuous by the bright colour 

 and large size of its polypes. It occurs attached to the bottom 

 of rock-pools at extreme low-water spring-tides, Shetland. 



