74 DR, W. RAE SHERRIFFS ON EVOLUTION 



there is no true crown, but there are small white spindles on the 

 soft polyp stalk, lying irregularly but on the whole transversely 

 and quite distinct from the coloured spindles of the supporting 

 sheath which lie longitudinally. It is plain that the uppermost 

 rows of these transverse spindles might furnish the raw materials 

 of a crown. 



The supporting bundle is of the ensheathing type and is often 

 very inconspicuous. The typical form is a curved triangle 

 around the polyp stalk, composed altogether of about a dozen 

 spicules, and those composing the tip are not conspicuously longer 

 than the rest. It is what might be called a slightly difierentiated 

 supporting sheath rather than a, supporting bundle, and its 

 comparatively small spindles must not be mixed up with the 

 large supports of the common stalk of the common bundle. The 

 supporting bundle oi:ily occasionally projects a little beyond 

 the polyp. Its component spicules do not attain a length of 

 more than 0*75 mm. 



7. Other sjncules. Very noteworthy is the spiculation of the 

 short, sterile stalk, where for a veiy limited area the spindles are 

 replaced by irregularly branched, almost stellate, bodies, which 

 interlock and give the surface an arenaceous appearance. Many 

 of the branchlet spindles are striking in their size, reaching a 

 length of 6 mm. They are densely covered with truncated 

 columnar tubercles which form regular curved transverse rows, 

 recalling the septa, of an elongated Fungia coral. The truncated 

 tops are very rough and sometimes compound. 



The colourless spindles of the general cortex are partly like 

 small editions of those just mentioned, and partly narrower forms 

 with distant and relatively few tubercles. They range from 

 l-2"5mm. The small "stellate" forms at the base are very 

 irregular in shape. Many are almost globular ; many are minute 

 quadriradiates ; many show one predominant boss among the 

 radiating knobs ; wdiile many again correspond exactly with those 

 figured by Kiikenthal for D. japonica (fig. L 6)*. 



Very few canal-wall spicules could be found. Those that 

 occurred very spai-ingly were narrow rodlets with a few distinct 

 tubercles. 



Deduction : — Although this splendid specimen has no uniform 

 contour it presents many resemblances to D. hrevirama (Burch.), 

 such as : 



(1) the anthocodial armature of 6-8 spicules in each point, the 



uppermost not projecting ; 



(2) the short polyp stalk ; 



(3) the numerous 2 mm. spindles of the general cortex ; 



(4) the crowded stellate bodies of the lower cortex ; 



(5) in the polyp - bearing twigs a corymbose - dichotomous 



branching, almost identical with that of specimens which 

 agree in detail with D. hreviraifna. 



* Kiikenthal, "Versncli einer Revision der Alcynarien." Zool. Jahrbcli. Jei;a. 

 System, vol. xxi. p. 576. 



