THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 73 



internodal septum which in tlie older hydrothecfe marks the base of the nematophore is 

 indicated in the terminal individuals only by a minute indentation. 



I think, with Nutting, that the general structure of the trophosome of the colonies 

 resembles that of Lytocarpus rather than that of Aglaophenia. 



Measurements : — 



Stem interiiodes, ltMij,'tli .... 0'39-0"45 mm. 



In-eadth .... 0-22-0-2+ „ 



Hydroclado internodes, length .... 0'38-0'42 .,- 



HydrotlieciK, lengtli *. .... 03.5 mm 



,, diameter at margin . . . O'lT ,, 



Mesial nematopliore, length .... 0'28 ,, 

 Supracalycine neniatophores, length of longest side, O'l 1 mm. at base 



0'14-0'17 mm. at di.stal end of hydroclade. 



if hvdroclade to 



long. 37 



58' W. 



Locality. — Station 81, Abrohlos Bank, Brazil. Lat. 18° 14' S. 

 Depth, 36 fathoms. Bottom deposit, coral. 20th December 1902. 



Distribution. — Only recorded from Florida Reef, in the Gulf of Mexico (by Allman), 

 and from a station in the Caribbean Sea (by Nutting). 



Aglaojiheina duhia, Nutting, 1900. 



Two specimens of this species, the A. gracilis of Allman's Gulf Stream Report 

 (Allman, 1877), were collected in the same locality — one .simple, reaching a height of 

 6 cm., the other sparsely bi'anched and rather longer. The anterior profile of the 

 hydrotheca is not so markedly concave as in Allman's figure, nor is the mesial 

 nematophore quite so long relatively to the height of the hydrotheca. The hydrothecae 

 have nine teeth (Nutting says "about eight"), of which one on each side lies behind 

 the supracalycine nematophores and is more acute than the others, while the anterior 

 tooth is usually recurved. The number of the basal nematophores differs from that 

 recorded by Allman and Nutting, for not only are two present on the front of each 

 stem-internode (one close to the hydroclade and one on the pro.ximal portion of the 

 internode), while another small one lies at the base of the hydroclade, close to the former 

 of those ju.st mentioned — but, in addition, a large cup-shaped nematophore exists on the 

 posterior aspect of internode, immediately behind the base of the hydroclade. Other- 

 wise the specimens agree, point for point, with previous descriptions. 



Measurements : — 



(ROY. SOC. EDIN. TRANS., VOL. XLVII., 95.) 



