Prof. Allraan on the Hydroida. 11 



extension, tliey are held with alternate tentacula elevated and 

 depressed ; body of polype oval, with proboscis conical. 



Gonophores medusiferous, borne by the creeping stolon and 

 elevated each upon a rather long peduncle. Medusoids dome- 

 shaped, with the vertical slightly exceeding the transverse dia- 

 meter ; manubrium reaching to about one-half the depth of the 

 bell, with a simple mouth destitute of tentacula ; marginal ten- 

 tacula two, opposite, very extensile, and with large reddish-orange 

 bulbous bases, without e\ddent ocelli, the intermediate radiating 

 canals terminating each in a very small bulbous dilatation. 



Growing over the stems of Plumularia setacea, dredged from 

 about 12 fathoms, Tor bay. 



Perigonymm minutus, mihi. 



Zoophyte very minute, consisting of simple stems rising to the 

 height of about 1^ line from a creeping stolon, and bearing 

 the polypes upon their summit ; polypary dilated round the base 

 of the polype. Polypes ash-brown, with seven or eight, rarely 

 twelve, tentacula, held irregularly during extension, and with 

 little or no curvature. 



Gonophores pyriform, medusiferous, borne at various heights 

 upon the stem, and supported on rather long peduncles. Me- 

 dusoid with the summit suddenly contracted, so as to give a 

 somewhat conical form to the nectocalyx, and having two opposite 

 radiating canals terminating each in a pale brown bulb which is 

 continued into a very extensile filiform tentaculum, and two alter- 

 nate canals terminating each in a much smaller bulb without 

 tentacle ; no evident ocellus ; manubrium short, with a four-lobed 

 lip, but without oral tentacula. 



Forming a fringe round the edge of the operculum of Turritella 

 communis dredged in Busta Voe, Shetland. Out of between twenty 

 and thirty specimens of living Turritella examined, not one was 

 free from this remarkable little Zoophyte. 



The present species manifestly comes very near to Atractylis 

 repens of Dr. T. S.Wright. Judging, however, from Dr.Wright^s 

 description and figures (Proc. Roy.Phys. Soc.Edinb.l858,p.450, 

 pi. 22. figs. 4, 5), Perigonymus minutus diflfers from A. repens, 

 "Wright, in the form of the umbrella of the mediisoid, which in 

 A. repens shows no approach to the conical figure presented by 

 the species here described, and in the entire absence from the 

 medusoid (at least at the time of its liberation) of the small inter- 

 mediate tentacula. It also comes very near to the Eudendrium 

 pusillum of the same author {op. cit. 1857, p. 231, pi. 11. figs. 8 

 & 9) ; but the conical form of the medusoid separates it also 

 from this species, from which it still further differs in the much 

 longer peduncles of its gonophojres. 



