NORTH SIDE OF THE BAY OF BISCAY, AUGUST, 1906. 21 



hydraiiths and gonophores are directly connected \vith the axial tube, 

 and the auxiliary tubes only give rigidity to the stem and branches. 

 The auxiliary tubes greatly increase the thickness of the stem and the 

 principal branches, and extend, in decreasing numbers, almost to the 

 extremities of the little branches, but do not run along the stalks of 

 the hydranths. 



The hydranths (PI. I., Fig. 1) have rather a broad, cone-shaped hypo- 

 stome surrounded by a single row of about twelve tentacles, but oc- 

 casionally thirteen are present. It is not possible to say definitely that 

 the tentacles during life naturally arrange themselves in two altern- 

 ating series, one elevated and the other depressed, as in Bougainvillia. 

 A few of the hydranths certainly show such an arrangement, but as 

 nearly all the hydranths are in a contracted or semi-contracted 

 condition, the tentacles are also contracted. Surrounding the lower 

 part of the hydranth is a cup-like expansion of the perisarc, into 

 which the hydranth withdraws on contraction. This cup is conspicuous 

 owing to its being covered with very fine black or dark brown 

 particles. A similar coating occurs in Bimeria vestita and Bougain- 

 villia. The stalks of the hydranths are smooth, except at their origin, 

 where there are a few slight wrinkles or corrugations. The axial tube 

 is also smooth, but it is only exposed just at the tips of the branches. 



The gonophores (Fig. 3) are situated upon the branches, and not 

 upon the hydranths or their stalks. The male gonophore is globular 

 in shape, and is upon a short pedicel. Sections (Fig. 2) show that it is 

 a true sporosac. At the base of the spadix slight outgrowths of the 

 endoderm indicate rudimentary radial canals, such as are found in the 

 gonophore of Garveia nutans. 



Bimeria biscayana, nova species. Plate I., figs. 4, 5. 



At Station XI [1., 412 fathoms, six colonies of a small Hydroid, 

 about 20 mm. or less in height, were found attached to the coral 

 Lophohclia. As the colonies have compound branches of considerable 

 thickness for the size of the colonies, and are without, gonosomes, they 

 are probably at an early stage in their growtli, and may reasonably be 

 expected to grow to a much larger size. 



Description of the species. Hydrocaulus compound, composed of 

 series of tubes bearing individual hydranths. Some of the stems of 

 the hydranths become branches. Hydranths with aljout ten tentacles 

 in a single verticil. Perisarc continued over the lower part of the 

 liydranth in the form of a small cup, into which the hydranth con- 

 tracts. Gonosome unknown. 



Theoretically, the main stem of the colony should be a single 

 unbranched tube carrying a hydranth at ils top. The hydranth 



