new Species of Hydroids. 365 



several cases round bodies greatly resembling acrocysts were 

 seen resting on the top of these gonangia. The other kind 

 of gonangia (male?) was much longer, more slender, and but 

 slightly curved. None of the gonangia were annulated. 



Locality, — Plymouth Sound. 



Habitat. — Found growing on Antennularia ramosa. 



This delicate species bears considerable general resem- 

 blance in size, form, and parasitic habit to P. halecioides. 

 It differs, however, in having a non-fascicled stem, smaller 

 hydrothecaj, more numerous nematophores, and especially in 

 the gonangia, which are greatly unlike the annulated struc- 

 ture of P. halecioides . 



Aglaophenia Ilelleri, Marktanner-Turneretscher *. 

 (PI. XVI. figs. 1-4.) 



This species was collected by Mr. Allen on May 8th from 

 beneath the overhanging shelf of rock below the remains of 

 the old lighthouse at the Eddystone, where it was growing in 

 considerable quantity f. This is the first record of A. Heller i 

 on British shores. 



Trophosome. — Colony unbranched, attaining a height of 

 f inch. Stem monosiphonic, divided by very deep nodes 

 into short internodes, each bearing a hydrocladium springing 

 from its antero-lateral aspect. Hydrocladia alternate, closely 

 set, divided into internodes, each bearing a hjdrotheca and 

 partly divided by two imperfect transverse septa. Nodes 

 very distinct. Hydrothecai obconic, about as deep as the 

 aperture is wide. Marginal teeth 9, unequal in size, the 

 anterior one often being slightly incurved and rather longer 

 and more pointed than the others ; the second and fourth teeth 

 counting from behind are larger than the first and third. 

 There is no apparent intrathecal ridge. Supracalycine nema- 

 tophores rather small, stout, reaching to the level of the 

 hydrothecal margin j the mesial nematophore springs from 

 just below the margin of the hydrotheca and projects straight 

 upwards and outwards, its truncated end reaching to the level 

 of the longest marginal teeth. There are two modified nema- 

 tophores on each hydrocladium near its base. 



Gonosome (description from Naples specimen). — Corbula 

 thick and short, with the leaves or ribs more closely soldered 

 together than in the other small British species. Kibs six on 

 each side, with a row of nematophores on their distal edges. 



* * Die Hvdroiden des k. k. naturhistorischeu Hofmuseums,' Vienna, 

 1890, p. 271,* pi. vii. 

 t 'Journal of the Marine Biological A.ssoeiation,' n. s. iv. p. 40. 



Aim. & Mag. N. Hist. Ser. 7. Vol. i. 2b 



