ON THE HYDROIDS OF THE SCOTTISH NATIONAL ANTAECTIC EXPEDITION. 73 



Lafo'ea gracillima (Alder, 1857). 



Several specimens referable to this species occur growing on the horny axis of an 

 Alcyonarian. They agree in all but size with the specimens described by BONNEVIE 

 (1899), the largest reaching a height of only 3 cm., while the general size lies 

 between 2 and 3 cm. The colonies are erect and branched, without any distinct 

 stem, the greater number of the branches lying in one plane and showing a tendency 

 to be more strongly developed on one side. Except towards the tip, where they are 

 monosiphonic, the branches are fascicled. The hydrothecse are long narrow cylinders 

 0'5 mm. in length by O'l mm. in greatest diameter, sometimes with reduplication 

 rings round their margins. They arise irregularly from all sides of the hydrocaulus, 

 and are borne on loosely twisted peduncles bearing two turns of a spiral. 



Gonosome. Not observed. 



Locality, etc. Growing on the axis of an Alcyonarian (Gorgonid) in 56 fathoms. 

 Date, 1st December 1903. Burdwood Bank. Lat., 54 25' 8. ; long., 57 32' W. 



Grammaria magellanica, Allman, 1888. (PI. I. figs. 4, 4A.) 



Three colonies varying in height from 6 cm. to 16 cm., and in breadth from 7 cm. 

 to 12 cm. The stem is fascicled and thick, reaching just above the base a diameter 

 of about 3 mm. and gradually tapering towards its summit. In two of the specimens 

 it divides about 1 cm. above the base into two or three equally developed, strong 

 branches, and these, together with the stem itself in the other specimen, bear along 

 their length usually alternate ramuli, which sometimes reach a length of 14 cm. 

 These primary ramuli bear secondary, and these again may bear tertiary, pinnae-bearing 

 branches. On all the branches, and on the main stem between the branches, there are 

 alternately-set pinnae usually between 10 mm. and 15 mm. in length, which become 

 greatly constricted at their point of origin. All the branches and pinnae lie in one 

 plane, and in the largest specimen anastomosis occasionally occurs between them. The 

 hydrothecse are placed in successive planes, in whorls of three, which alternate with 

 one another so that there are six longitudinal rows on the colony. They are cylindrical, 

 and have a circular opening with an even, non-everted margin. 



Gonosome. The gonangia are grouped together into irregular bunches which 

 surround portions of the stem and the bases of such branches as arise from these 

 portions. In the largest of the three colonies two bunches of clustered gonangia were 

 found, the larger 30 mm. long by 3 mm. in diameter, the smaller 20 mm. long by 

 about 2 mm. in diameter, while on another colony a still smaller cluster occurred. 

 These coppinias are elongated clusters of compressed gonangia growing closely around 

 the stem for a considerable distance, and bristling with minute projecting tubes which are 

 without the irregular bendings figured by HARTLAUB (1905). Under the microscope the 

 cluster resolves itself into a large number of hexagonal cells, closely resembling honey- 



(ROY. soc. EDIN. TRANS., VOL. XLV., 531.) 



