140 



vol. xxxi.), but this shape may again be a result of contraction. We feel that 

 little stress should be laid on such points. 



The polyps are cylindrical and are about 2 mm. to 3-6 mm. in length and 

 rS mm. in diameter. The spicules are arranged in eight indefinite groups 

 which in some places form distinct ridges. They are disposed so that the groups 

 point slightly upwards "en chevron," but towards the top of the polyp they 

 often become almost horizontal, though no trace of a collaret as in Sdenmephthiia 

 pustulosa (Wright and Studer) can be said to exist. Above this region the 

 spicules are distinctly "en chevron" and form eight triangular figures, each 

 composed of three to five spicules. These close over the retracted tentacles. 



The tentacles also bear small spicules on their aboral surface. 



Locality : Gaspar Strait, E. Coast of Sumatra. 



GENUS STEREACANTHIA, Thomson and Henderson. 

 Stcreacanthia indica, Thomson and Henderson. 



We have referred the genus Stereacanthia to the sub-family Siphonogorgime 

 on account of the internal structure of the stalk. Bourne in his classification 

 of the Alcyonaria (in Lankester's "Treatise of Zoology," Part II., Coelenterata) 

 defines the Siphonogorginte as having " Canal walls densely filled with spicules ". 

 In Stereacanthia indica, Thomson and Henderson, not only are the canal walls 

 packed with spicules, but the latter are extremely large and give great rigidity 

 to the colony ; some of them attain a length of 7 mm. 



There can be little doubt that the Siphonogorgids are closely connected to 

 the Nephthyids, as Kiikenthal points out, through types like Stereonephthna , 

 and, in addition, there are external resemblances between species of Sterea- 

 canthia and some species of Eunephthya, notably, E. spiculosa, Kiikenthal. 



But species with the canal walls of the stalk thicUy filled with kirge 

 spicules, which give great rigidity to the colony, cannot be referred to a genus 

 whose diagnosis includes the character " Canal walls not thickly filled with 

 spicules ". A cross section of the stalk of a typical Eunephthyid, e.g., Eiinephthya 

 ro^ea, is entirely different in appearance from that of Stereacanthia. The 

 armature of the polyps is also very much heavier and more like the " crown 

 and points " arrangement of the Siphonogorgid type. 



It is interesting to note the occurrence in this collection of a young sijecimen 

 of this species described in the " Report on the Deep-sea Forms ". Two main 

 stems, 3'2 cm. and 3 cm. in length, with a maximum breadth of 1 and 1-5 

 cm. respectively, arise from a spreading base. Both are flattened slightly in 

 one plane. In one of them a considerable portion is devoid of polyps, so 

 forming a kind of stalk, above which the polyparium extends with no great 

 difference in diameter. Polyps occur on the other almost to the very base. 



