175 HYDROIDA. BALE. 



edge of the operculum rests, and above which it seems to be 

 hinged. The large sarcothecse sin-round the base of the gono- 

 theca like a calyx ; in most cases I found five or six, but in 

 others there were not so many. 



My first specimen was extremely dark in colour, almost black 

 indeed, as are some of those in the present collection. But there 

 are several colonies of very pale colour, which present a striking 

 contrast to the others ; they are also rather more lax in growth, 

 with the branchlets further apart. After careful examination, 

 however, I can find no sufficient ground of separation. The 

 colour of the black form is due less to the perisarc than to the 

 remains of the soft parts, which are so opaque as to render it 

 impossible in most cases to see the details of the polypidom. In 

 the pale variety the remaining soft tissues are quite light in 

 colour, and there was no difficulty in the examination. When 

 studying the original specimen I did not find more than two 

 hydrothecaa fairly clear, the figure however was correct except in 

 the position of the sarcotheca? behind the hydrotheca, which were 

 facing outwards ; their more usual position seems to be facing 

 iipward. 



Loc. Bass Strait, 4-0 fathoms (type form) ; fifty miles south 

 of Cape Wiles, South Australia, 75 fathoms (both forms). 



Genus AGLAOPHENIA, Lamonroux (in paii.) 

 AGLAOPHENIA ARMATA, sp. nov. 

 (Plate xxxviii., figs. 3-4.) 



Hydrophyton nearly a foot in height, polysiphonic, branched 

 freely and irregularly, mostly in the upper portion, branches 

 springing from the front of the primary tube, between the bases 

 of the hydrocladia, internodes supporting each a hyclrocladium 

 but the nodes often indistinct. Hydrocladia alternate, close, 

 divergent at about 45 or 50, nearly in one plane, nodes 

 transverse or slightly oblique. 



Hydrotheca? borne nearly on the front of the hydrocladia, 

 closely set at a wide angle, long, tubular ; a strong intrathecal 

 ridge a little above the base, originating at the back angles of the 

 lateral sarcotheca?, and extending fully half through the cell, and 

 directed somewhat downward ; border with a rather large straight 

 pointed median anterior tooth, and three teeth on each side, back 

 very deeply excavated. Two septal ridges in the internode, one 

 under the front of the hydrotheca and one under the lateral 

 sarcothecaa, very often a third between them. 



