OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 859 
two opposite sides of the branches, although by no means confined to these. They are 
not wholly retracted, but protrude from the surface of the coenenchyma as small 
roundish warts surrounded by a gently sloping spicular dome, which rises gradually to 
form a very slight lip around the polyp aperture. . 
The spicules, which are whitish and translucent, are of three main types. (a) Most 
abundant are long narrow spindles, e.g. 0°75 x 0:06, 0°7 x 0°05 mm., covered with warty 
tubercles, which are frequently produced into blunt spines. The spines show a marked 
tendency to unilateral development, being often more prominent and more numerous on 
one side of the spindle. () Less abundant are scaphoid forms, ¢.g. 0'7 x 0°12, 0°4 x 0°06 
mm. (c) There are also some forms which approach the ‘club’ type and differ greatly in 
size, e.g. 0°45 x 0°12, 0°25x 0:06 mm. Their heads are covered with long blunt pro- 
cesses, similar to the blunt spines of the spindles, and these are sometimes continued 
down the ‘handle’ of the club. Both the ‘scaphoids’ and the ‘clubs’ are readily 
derivable from the spindle type. . 
We have named this new species G’. studer after Prof. TH. SrupER, joint-author of 
the Challenger Report on Aleyonarians. 
Locality.—Station 81 ; lat. 18° 26’ S., long. 37° 58’ W. ; 40 to 50 fathoms. 
Famiuy UMBELLULIDA. 
Umbellula durissema, Kolliker, Pl. I. fig. 5. 
About twenty specimens of this beautiful form were obtained from one locality, 
from a depth of 1742 fathoms (April 13, 1904). Only one specimen was obtained by 
the Challenger expedition, and that much younger and smaller than the best of the 
Scotia specimens. 
The following total length measurements were taken :—50, 45, 42, 37, 34, 32, 22, 
20,18, 17cm. The heads vary from 2°8 cm. in height and breadth to 1°7 in height 
by 0°5 in breadth. ‘he stalk is very slender in proportion to the head, and the follow- 
ing breadth measurements were taken :—3°5 mm. almost at the base and 1 mm. near 
the top of the largest specimen ; 1°5 mm. at the base and 0°5 mm. near the top of the 
smallest specimen. 
There is considerable diversity in the number of polyps—thus one head had 9, one 
had 7, five had 6, one had 5, and four had 3 polyps. The colouring of the polyps is 
exceptionally beautiful—a milky blue fading basally into white; the tentacles are 
chocolate brown. Hight vertical rows of rod-like spicules extend up the surface of the 
polyps and are continued into the tentacles. The largest polyps measure 15 mm. by 
8 mm., not including the tentacles, which are 15 mm. in length. The minute siphono- 
zooids are exceedingly numerous, covering the whole ventral surface of the head except 
a narrow median ridge, and also extending in bands between the bases of the polyps or 
autozooids. ‘The bluish colour was not noticed in the Challenger specimen, and 
seems to be gradually fading in those under our observation. 
TRANS. ROY. SOC. EDIN., VOL. XLI. PART III. (NO. 33). 126 
