HYDROIDA. — BALE. 37 



ing between 17 and 18 mm., and comprising about thirty-six 

 pairs of leaflets ; many however, are less than half this length. 



Loc. — Great Australian Bight, 40 to 100 fathoms. 



Ac.LAOPHF.NIA TASMANICA, Sp. nor. 



(Plate iii„ fig. 2; Plate vi., fig. 2.) 



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 50° ; each branch springing from an internode of the 

 primary jointed stem and replacing a hydrocladium. Hydrocladia 

 alternate, one on each internode, both series directed towards the 

 front and rising at angles of about 40°, nodes slightly oblique. 



Hydrothecae 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 adcanline side, directed a little 

 forwards ; some with a blunt rounded tooth projecting into the 

 cavity from the front, a little above the base ; border with a 

 sharp pointed anterior tooth, and a triangular tooth on each side 

 near the front, the rest of the. border rather sinuous at the sides 

 but not forming elevated lobes ; no angular lobes behind the 

 lateral sarcothecae ; back excavated, adnate. Hydrothecal 

 internodes with septal ridges opposite the intrathecal fold and the 

 base of the lateral sarcothecae. 



Mesial sarcothecae two-thirds to six-sevenths as long as the 

 hydrothecae, closely adnate throughout, aperture simple, per- 

 pendiciilar to the hydrotheca or slightly oblique. Lateral 

 sarcothecae tubular, directed forward and outward, scarcely pro- 

 jecting beyond the hydrotheca-margin ; aperture small, round, 

 canaliculate. Cauline sarcothecae broad, completely open above, 

 two on the rachis at the base of each hydrocladium. 



Gonangial pinna? mostly in pairs, with the first three or four 

 internodes bearing sarcothecae only. Corbula (female) Jong, con- 

 sisting of up to about fifteen pairs (or more ?) of alternate ribs, 

 springing from separate internodes of the rachis as narrow 

 pinnules, but expanding above into broad leaflets, which unite 

 to form a closed corbula ; the distal margin of each leaflet 

 continued a little beyond the line of union so as to form a free- 

 edged narrow extension or wing, bordered with sarcothecae 

 and continued upwards into a very large crest above the 

 corbula, having both edges free and bordered with sarcotheca* ; 

 a lateral spur or secondary leaflet projecting outwards and 



