HYDROIDA. BALE. 33 



Of the species hereinafter described A. tasmanica and A. billardi 

 were successively submitted by me to Dr. Billard in order to 

 obtain his opinion as to their identity or otherwise with 

 A. crucialis. After carefully examining them he considered that 

 the first, while differing from A. crucialis in some minor 

 particulars, might be considered specifically identical with it, and 

 that the second could be regarded as a distinct species, though 

 very closely allied. I have, however, judged it more convenient 

 to consider A. tasmanica also distinct, at least pi-ovisionally, and 

 subject to its reduction to the rank of a variety (either of 

 A. crucialis or A. billardi), should further investigation 

 show the advisability of such a classification, I should 

 indeed have no hesitation in regarding A. tasmanica 

 as distinct from A. macrocarpa, if these forms only were in 

 question, but it is at present doubtful how far they may be linked 

 by intermediate forms such as Ritchie seems to have observed. 

 Not only have I had no opportunity of observing typical forms of 

 A. crucialis, but I have not seen a complete specimen of 

 A. macrocarpa, but only two fragments, that from which I 

 originally described it, and another which Mr. R. Etheridge, Junr. 

 was good enough to send me recently from the Australian 

 Museum for comparison. Moreover, these two specimens differed 

 considerably in colour and ramification, though identical otherwise. 

 The first had, as I indicated in my original description, no 

 opposite branches, but two on the same side, while it was of a 

 deep red-brown colour, almost black in the stem and branches. 

 The other specimen has two pairs of opposite branches, and is 

 almost colourless. It is just possible, however, that the colour may 

 have been discharged by the fluid in which it had been preserved, 

 especially as a Halicornaria parasitic upon it — H. tlietidis 

 Ritchie— appeared equally bleached. But Ritchie does not 

 mention the colour, either of H. tlietidis or A. crucialis. 



Aglaophenia billard:, sp. nov. 

 (Plate Hi., fig 3 ; Plate vi., fig 3.) 



Hydrophyton polysiphonic, about a foot in height, sparingly 

 branched above ; branches mostly in opposite pairs, both series in 

 one plane and all facing one way, forming angles with the stem 

 of about 45° ; each branch springing from an internode of the 

 primary jointed stem and replacing a hydrocladium. Hydrocladia 

 alternate, one on each internode, both series directed slightly 

 towards the front and rising at angles of about 4<J U , nodes 

 slightly oblique. 



Hydrotheca? long, at an angle of about 30°, nearly cylindrical 

 in their distal half, narrowed towards the base, a slight fold or 

 ridge near the base on the adcauliue side, directed a little 



