[66] MB. JAMES RITCHIE ON HYDROIDS [May 28, 



The mesial nematophore is long (almost 0'3 mm.), reaching- 

 O'Oo mm. above the level of the hydrathecal margin, adnata for 

 little more than half its length, and with two apertures. The 

 supracalycine nematophores are divergent, long and tubular, 

 inclined at an angle similar to that of the mesial nematophore. 

 and rising a short distance above the margin of the hydrotheca, 

 to which they are adnate. On each stem-internode there are two 

 triangular nematophores, one proximal, the other distal to the 

 base of the hydroclade, while the ba,se itself bears anteriorly a 

 tubular nematophore. 



Gonosome. — The gonangia aie borne on modified recurveil 

 hydrocladia, divided into al)0iit ten short internodes, the proximal 

 bearing a hydrotheca, which is replaced on the following two or 

 three internodes by a gonangium. Each of the remaining inter- 

 nodes bears one or two divergent tubular nematophores, each with 

 two aj^ertures, one terminal, the other in the angle formed between 

 nematophore and internode. The gonangia are almost circular, 

 and are much compressed. As many as twenty-two gonangia on 

 eight phylactocarps wei-e counted on one specimen. The arrange- 

 ment of the nematophores on the phylactocarp suggests that which 

 occui'S in connection with the hydrotheca?, two divergent nemato- 

 phores frequently occurring at the same level and beneath them 

 a single mesial nematophore. 



Locality. Growing on a leaf found in a bottle containing 

 tunicates from Mattiota, St. Vincent Harbour. 



The trophosome of the present species is almost identical with 

 that of Aglaophenia plumosa Bale (1884), but there the recurved 

 gonangial pinna bears " 15-20 pairs of alternate pinnules," these 

 again bearing the nematophores which are arranged diffei'ently 

 from those in the specimen before me, the whole structui'e forming 

 a corbula. 



List of Literature cited. 

 Alder, J., 1859. — "Description of two new Species of Sertularian 



Zooph>-tes, found on the coast of Northumberland " ; Ann. 



Mag. Nat. Hist. 3rd ser. vol. iii. 

 Allmas, G. J., 1864. — "Notes on the Hydroida"; ibid. 3rd ser. 



vol. siv. 

 Allmax. G. J., 1871, 1872. — A Monogi-aph of the Gymnobla-stic 



or Tubularian Hydroids. Ray Society. London. 

 Allmas, G. J., 1877. — " Report on the H^-droida collected during 



the exploration of the Gulf Stream." Harvard Mus. Zool. 



Mem. 5. 

 Ai.lmax, G. J., 1883.— " Report on the Plumularians." 'Chal- 

 lenger' Expedition, Sci. Reports, Zool., vol. vii. 

 Allman, G. J,, 1888.—" Report on the Hydioids," Part II. ; ibid. 



vol. xxiii. 

 Bale, W. M., 1884. — A Catiilogue of the Australian Hyilroid 



Zoophytes. Sydney. 

 Benedex, p. J. VAX, 1844. — " Recherches sur I'Embr^yogenie des 



Tubulaires"; Nouv. Mem. de I'Acad. de Brux., tome xvii. 

 Billard, a., 1904. — "Contributions a I'etude des HydroJdes"; 



Ann. des Sci. Nat. ser. 8, vol. xx, 

 512 



