470 Rev. T. Hincks on Reticularia immersa and Halia prsetenuis. 



is greatly altered,— the cells are sparingly distributed along 

 the fibre, and the difficulty vanishes. Both Prof. Thomson and 

 myself overlooked the fact, that the production, which we re- 

 spectively designated as Reticularia and Halia, had been pre- 

 viously described by Mr. Hassall in the Transactions of the 

 Microscopical Society (vol. iii. p. 163) under the name of Cam- 

 panularia serpens, Mr. Hassall^s description may not perhaps 

 be as full and precise as might be desired, but it is sufficient for 

 the identification of the species. There is no doubt that it has 

 no claim to a place in the genus Campanularia, and that Prof. 

 Thomson was right in constituting a new genus for its recep- 

 tion. The name Reticularia^ therefore, must be retained, but 

 Mr. HassalFs specific designation is entitled to precedence. 

 The characterization may be revised as follows : — 



Order Hydroida, 



Fam. *. 



Genus Reticularia. 



Polypidom " a parasitical, investing network of horny tubes, 

 immersed in a horny crust;" cells decumbent, adherent, irre- 

 gularly disposed along the fibre, to which they are attached at 

 the base. " Polype of a greenish colour, with numerous smooth, 

 solid tentacula ; very minute." 



Reticularia serpens. 



Campanularia serpens, Hassall, Microscop. Transact, vol. for 1852. 

 Reticularia immersa, W. Thomson, Annals, vol. xi. for 1853. 

 Halia preetenuis, Hincks, Annals for Febr. 1855. 

 Capsularia serpens, Gray, List of Brit. Radiated Animals, p. 161. 



Cells elongate, with upturned, terminal, and more or less 

 tubular orifices, inoperculate, and with even rim. 



The polypidom is a creeping fibre of great delicacy, which 

 forms an irregular network, corneous and closely adherent ; it is 

 invested by a kind of crusty which, when the zoophyte is in a 

 recent state, gives it a soft and spongy appearance, but is not 

 apparent when it is dried; the cells, which occur sometimes in 

 pairs, one on each side of the fibre, sometimes singly, sometimes 

 in companies, are elongate, attached by the base to the poly- 

 pidom, adherent, except at the anterior extremity, which bends 



* I do not associate Reticularia with any of the existing families of 

 Hydroida, fully agreeing with Prof. W. Thomson in the opinion that the 

 section of the' genus Campanularia which embraces C. syringa, dumosa, 

 parvula (and to these may now be added the C. gracillima (Alder)), 

 together with the genera Coppinia and Reticularia, should form a distinct 

 group " intermediate between the Sertularians and the Campanularians." 



