228 MR. S. O. RIDLEY ON THE CORALLIID^. [Feb. 7, 



considerable depth at which this specimen was obtained, not being 

 greater than that from which Corallium is brought to the surface 

 in the Mediterranean, need not of itself prevent such an undertaking. 



Pleurocorallium secundum, Dana, var. elatior. (Plate IX. 

 figs. 6-11). 



Branching normally in one plane. Stem strong, oval in trans- 

 verse section, the longest diameter being the lateral one. Mode of 

 branching normally dichoton.ous combined with pinnation. Distance 

 between points of origin of main branches considerable, but sides of 

 branches occupied in these intervals by small branches or pinnae, 

 irregular in size and point of occurrence, occasionally found on the 

 anterior surface ; branches of main system decreasing gradually in 

 thickness to the extremity of the corallum, somewhat tortuous, 

 decidedly compressed from front to back in most places, the lateral 

 diameter being to the antero-posterior about 11:9; pinnse short, 

 coming rapidly to a point, circular (or almost so) in transverse 

 section, generally curved or tortuous, and not exceeding 20 mm. ia 

 length. Axis of corallum hard, not easily indented with a knife, 

 solid ; in main stem, and for a considerable distance up the main 

 branches, of a deep crimson-red colour with a tinge of scarlet, 

 resembling the colour of dried salmon's flesh ; in the upper branches 

 and the pinnse the central portion of the axis becomes paler, being 

 at first pink and finally white, this axial pale tract widening as it 

 approaches the extremity of the branches or pinnse, the axes of 

 whose apices are white throughout. Surface of hard axis very 

 finely striated in the longitudinal direction, with about five striae to 

 1 mm., more deeply striated on smaller branches and pinnae ; surface 

 otherwise even, with the exception of a tendency to roughness at the 

 ends of the pinnse, and very slight (almost imperceptible) shallow 

 depressions beneath the calicles. Cortex about "3 mm. in thickness, 

 completely concealing all inequalities of the axis, except at ends of 

 pinnae ; friable, of a pale vermilion colour ; posterior and lateral 

 surfaces even, and devoid of verrucas, with the exception of a few 

 scattered ones on and near the stem and at the ends of some pinnae ; 

 anterior surface beset with verrucae at intervals of 1 to 3 mm., and 

 with minute punctiform elevations, visible only by the aid of a lens, 

 uniformly distributed over the intermediate spaces to the number of 

 about 25 in a square millimetre. Verrucae broad, truncate above, 

 rising abruptly from surface ; of same colour as the general cortex ; 

 in retraction they may be completely closed ; wrinkles between the 

 8 valves generally obsolete or very slight in the retracted state ; dia- 

 meter of verrucae 1 to 1'25 mm., projection from cortex about -5 mm. 



Spicules of cortex of two kinds, viz. : — (i.) Cylindrical, sexradiate, 

 colourless, with short thick axis ; at each extremity two tubercles 

 project from the side of the shaft (which does not project beyond 

 them), at right angles to it ; on each of the anterior and posterior 

 aspects of the spicule (reckoning those which bear the above-mentioned 

 four tubercles as the lateral ones) one tubercle is set at right angles 

 to the long axis of the shaft, near its extremity, but at opposite ends 



