1. IDJIOXKA. 13 



transversa of Milne-Edwards ; but as there is every reason to believe 

 that what M. Milne-Edwards has described and figured under that 

 name is really /. mihicana, D'Orb., and as his figure, at any rate, 

 will in no Avay suit the present form, it is impossible to place them 

 together, even were it right in any case to adopt Lamarck's specific 

 appellation, which was clearly applied by him, not to any form of 

 Idmonea, but to a parasitic TuhuVipora, probably T, serpens. 



6. Idmonea marionensis, n. sp. (Plate XIII. figs. 3-5, 

 Plate VII. figs. 7, 8, young state.) 



Zoarium slender, elongated, very sparingly branched ; stem and 

 branches cylindrical; cells 2-3 in a series (more usually 2), series 

 wide apart. Surface very finely and sparsely punctured ; dorsal 

 surface convex, with a fine longitudinal striation. 



? Crisina hoehstetteriana, Stoliczka, Novara Exp. Geul. Th. Bd. i. p. 1 1.3, 

 tab. xviii. fig. 3 ; Snutt, Floridan Bryozoa, p. 6, pi. ii. figs. 11-13. 



Hah. Marion Island, 80 fathoms ( Voij. Erebus 4' Terror, ) ; ? Gulf 

 of Florida, Bahia {Smitt, fossil) ; Orakei Bay, Auckland, New Zea- 

 land (StoUczlxi). 



This species marks a transition between PMSfi/Zo^jora a,nd Idmonea. 

 The cells, however, are always placed in rows or series on each side 

 of the anterior aspect of the branch and deeplj' immersed. It may 

 possibly be identical with M. d'Orbigny's /. canariensls (Pal. Erang. 

 p. 732) ; but as no figure or description of that species is given, and 

 it is merely stated to be " slender as a thread and almost round, 

 with very few cells," it is impossible to be certain. 



7. Idmonea irreg^aris, Meneghini. (Plate XII.) 



Zoarium branched dichotomously ; branches slender, rounded ; 

 cells -1—6 in each series, the outermost of which are the longest. On 

 the front of the branch, between the lateral series, the surface pre- 

 sents the openings of scattered cells. 



Idmonea in-egularis, Meneghini, Mem. sui Polypi delta Famiylia dci 

 Tuhidiporiani, p. 12 (teste Heller); Helkr, I. c. p. 121. 



Hah. Adriatic, on the Dalmatian coast {Menegh., Heller) ; Medi- 

 terranean (H.M.S. 'Porcupine''). 



Like /. marionensis, which has some of the characters of a 

 Pustidopora, the present form may be regarded as passing into 

 Hornera. 



8. Idmonea parasitica, n. sp. (Plate X. figs. 2, 3.) 



Zoarium irregularly branched ; branches slender, straggling, 

 often anastomosing ; cells slender, in great part free, and curved in 

 various directions, 2-5 in each series ; surface smooth, dotted. 



H((h. South Australia, parasitic upon Pmtulopora infricaria 

 (Gould). 



