AicroNARiA. 357 



carefully and found that, in the proportion of about 1 to 30 of the 

 ordinary verruose, or about one to each internode, some large verrucae 

 occurred, about twice the diameter of the usual forms ; this was the 

 case only on the medium-sized and larger branches. Unfortunately 

 no spirit-specimens of the species were obtained ; but the exami- 

 nation of the open verrucae shows 8 short spiculate tentacle-lobes, 

 converging like the segments of an orange, within both the smaller 

 and larger verrucse. This is therefore a case of dimorphism much 

 less strongly marked than and of a different character from that of 

 the Pennatulida, and of Oorallium and Sarcophytum, where the 

 asexual zooids have no tentacles. Possibly, when spirit-specimens 

 are examined, it will be found that these two kinds of ,tentaculate 

 individuals represent the two kinds of "polypes" (viz. rudimentary 

 sexual and perfect asexual) which occur in Halisoeptrum (KoUiker, 

 • Pennatuliden,' p. 161) in addition to the sexual " zooids." 



In my descriptions I have employed the term " internode " for 

 the hard joints, and " soft joints " for the intermediate ones, as being 

 more appropriate and more conformable to the botanical usage than 

 the "joint" and "internode" employed by Gray {I.e.) to designate 

 these parts respectively. 



The new genus Pdlacaharia presents an exception to the usually 

 strongly marked bilateral symmetry in the arrangement of the 

 external parts of the corallum in this family. 



MELIIODES. 



Melitsea, Lamarck, MSm. du Mus. SSist. Nat. i. p. 410 (1815). 

 Melitodes, Verrill, Bull. Mus. Comp. Zool. i. p. 38 (1863). 



Axis, both hard and soft joints, traversed by longitudinal canals ; 

 cortical spicules of two kinds, viz. larger, fusiform, verrucose, and 

 smaller, nodular. As above stated, the first of these characters only 

 distinguishes Melitodes from Clathraria and Psilacabaria among 

 Melithseidse. 



32. Melitodes albitiacta. 

 (Plate XXXVII. figs. C-C" ; Plate XXXVIII. figs. 6, b'.) 



Corallum slight, branching in one plane. Stem slender, internodes 

 circular in section ; joints oval, little thicker than the internodes and 

 about half their length. Branchlets slender, undulating, almost all 

 anastomosing, forming chiefly elongate meshes. Diameter of inter- 

 nodes of the larger main branches 3 miUim., of terminal branchlets 

 1 miUim. Colour of general cortex in dry state white, beautifully 

 speckled with vermilion, that of verrucae and the contained polypes 

 orange-yeUow. Cortex very smooth, thin on stem, on terminal 

 branchlets forming about two thirds of the thickness of the branch. 

 Verrucas broad, slightly prominent, arranged in two alternating rows 

 on each side of the branches, but generally absent from the anterior 

 and posterior faces ; they are of two sizes, viz. : — (i.) abundant, low, 

 about '4 millim. in diameter at their base ; (ii.) about one to each 

 iuternodo on an average, more prominent than (i.), measuring about 



