69 



XI. A large Tuhularian (Tubularia regalis, Boeck) from. tlie. 

 Moray Firth. By Prof. J. Arthur Thomson, M.A. 



(Read 16tli December 1907.) 



On '-!3rd March 1907, the " Goldseeker," engaged in the 

 international scientitic exploration of the Xorth Sea, 

 dredged from a depth of 39 fathoms in the Moray Firth 

 (58° N., 2° 38' W.) a magnificent colony of a species of 

 Tuhularia, which seems to be an addition to the list of 

 British Hydroids. Through the kindness of Prof. D'Arcy 

 W. Thompson, C.B., I obtained the specimen for exam- 

 ination, and my conclusion is that it is referable to 

 Tuhularia regalis, described in 1859 from Spitzbergen by 

 Chr. Boeck. 



The beautiful cluster of polyps is about a foot in height, 

 and strikes one at once as larger and more substantial than 

 similar clusters of the common Tuhularia indivisa, which it 

 resembles in general colouring. The height of a single hydro- 

 caulus, measured apart from the interlaced tangle at the 

 base, varies from 7-10 inches, and to this the large hydranth 

 may add nearly another inch (20-22 mm.). The breadth of 

 the hydrocaulus is about 3 mm., and the largest hydranth 

 at its broadest part has, in the contracted preserved state, 

 a width of about 20 mm. There are 12-15 longitudinal 

 lines on the clear perisarc, corresponding to vermilion lines 

 on the ccenosarc which shine through. 



There are 32-36 proximal tentacles from 12-22 mm. in 

 length, and the maximum spread of the tentacles, measured 

 along a diameter of the circle which they form, is about 

 60 mm. The distal tentacles form a dense brush, consisting 

 of several close tiers around the mouth. From 76 to 92 

 were counted on various hydranths. Each distal tentacle 

 is about 4 mm. in length, 0'4 mm. across the base, tapering 

 to 0-1 mm. at the tip. 



Immediately above the bases of the proximal tentacles, 

 12 to 14 unbranched blastostyles or pendulous racemes 



