THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 71 



raised portion of the internotle on the near side of the hydrotheca ; a supracalycine pair, 

 each individual of which reaches just to the margin of the hydrotheca and rests upon 

 the end of an internodal projection stretching half-way across the hydrotheca ; and an 

 additional pair supplementary nematophores placed on the upper and exterior surface 

 of the supracalycine process, almost in the angle between that process and the inter- 

 node. The latter are extremely fragile and readily detached, so that in many cases 

 they are unrepresented but by a small pore in the wall of the supracalycine process, 

 indicating where they had been attached. The intermediate internodes bear a number 

 of nematophores varying from two to four, but three is the most frequent number. 

 Thus, in twenty intermediate internodes examined, eight bore two nematophores, eleven 

 bore three, while only one had four. On the athecate basal internodes, three of which 

 generally follow one another in close succession prior to the first hydrotheca, the 

 nematophores also vary. Of nine such, four had four nematophores, two had five, while 

 series of two, three, and seven nematophores were represented on one internode each. 



Measurements : 



Thecate internode, length * . . . 0'46 mm. 



Intermediate internode, length * . . . 0'57-0'91 mm. 



breadth . . . 0-07-0-087 



Hydrotheca, depth ..... 0'2 1-0'22 



,, diameter at margin . . . O17-0'21 



This species is closely related to Plumularia secundaria (L., 1789, p. 3854), which, 

 if the genus Antenella is to be preserved, and it seems a useful one from the point of 

 view of practical convenience, must be transferred to that genus. The present species 

 has been separated from A. secundaria on the strength of observations made by 

 MARKTANNER-TURNERETSCHER (1890, p. 252), PICTET and BEDOT (1900, pp. 27, 28), and 

 BILLARD (1907, p. 207), all of whom record the presence of a single nematotheca 

 immediately above the hydrotheca, whereas in our specimens the hydrotheca is flanked 

 by a pair of nematothecae in addition to the usual supracalycine pair. The athecate 

 internodes in the Scotia species are twice the length of those in A. secundaria, and the 

 other parts differ in their relative proportions, but little stress can be laid on so indefinite 

 and so variable a character. I am unable to distinguish A. natalensis, Warren, 1908, 

 from A. secundaria. 



Locality. Gough Island. Trawled at a depth of 100 fathoms. Bottom deposit, 

 Bryozoa and rock. 23rd April 1904. 



Aglaophenia allmani, Nutting, 1900. 



Two specimens are referred to this rare species. One is a comparatively small 

 colony, 6'5 cm. high, still retaining some fragments of the hydrorhizal tubes. The 

 other is a strongly fascicled branch, with a diameter of 1'5 mm. at its junction with 



* Measured from straight node to furthest point of oblique node. 

 (ROY. soc. EDIN. TRANS., VOL. XLVII., 93.) 



