78 Proceedings of the Royal Physical Society. 



to the Bathyjpathes-iy^Q, and from Brook's point of view 

 they illustrate dimorphism occurring in trios — two elongated 

 "gonozooids" with a globular "gastrozooid " between them. 



The axis of the stem and branches is dark brown in 

 colour when looked at with the naked eye. The spines, 

 broad at the base, and tapering to a point, arise at right 

 angles to the axis, and four longitudinal rows are visible 

 from one aspect. The movement of the gas and liquid 

 within the axis showed that it was hollow, as cross sections 

 confirmed. 



The specimens agree well with the description which 

 Brook gave of Bathypathes 2^citula, var. 2Jlenispina, e.g., as to 

 the acute angle between the lower branches and the four 

 rows of spines visible from one aspect. But it may be noted 

 that the "Challenger" specimen was only 12 centimetres 

 in length, and had only three pairs of branches. The type 

 specimen of B. pattda had, however, 9-11 brauches. 



The jar containing the specimens is labelled " Cod Bank," 

 1st December 1903. 



2. Bathyjmthes alternata, Brook. 



A fine and well-preserved specimen, measuring 24 cm. 

 in height by 18 cm. in breadth across the lowest branches, 

 seems referable to Bathypaihes alternata, of which the 

 " Challenger" Expedition also obtained but a single example. 

 Of the total height, 10 cm. go to the sterile part and 14 

 cm. to the pinnate frond. 



The specimen agrees in general with Brook's description, 

 but it is bigger and stronger, the branches are far more 

 numerous (20 on one side, 21 on the other), and the axial 

 spines are more regular. The " Challenger " specimen was 

 only 18"5 cm. in height, and had 12 branches on one side, 

 13 on the other. It was said to be more slender than 

 B. patula and with smaller zooids, but the reverse is the 

 case with Bruce's specimen of B. alternata, which is probably 

 older and more vigorous than the colony obtained by the 

 " Challenger." 



There is no locality marked for this specimen. 



