76 THE VOYAGE OF H.M.S. CHALLENGER. 



following species under the genus : — Pi'ymyioa Jlabellum, Ehbg., Primnoa gracilis, Milne- 

 Edw., and Primnoa plumatilis, Milne-Ed w. 



In 1870, in his Catalogue of Stony Corals, the name Callogorgia was changed by Gray 

 into Calligorgia ; a special genus, Plumarella, Gray, was founded for Callogorgia penna 

 {plumatilis), and the genus Calligorgia was confined to Gorgonia verticillata, Pall., 

 with which Gorgonia verticillaris, Esper., Prymnoa flahellum, l^hhg., Prym7wa verti- 

 cillaris, Ehl)g., and Primnoa gracilis, Milne-Ed w., were placed as synonyms. The genus 

 Calligorgia falls under tlie family of the Calligorgiadas, which contains very heterogeneous 

 materials. In the diagnosis of the genus we again have the character that only three cells 

 form a whorl, while in the diagnosis of the only species varieties are mentioned at one 

 time with ten to twenty cells, at another time with four cells in a whorl. Studer in the 

 Alcyonaria of the voyage of the "Gazelle," 1878 {loc. cit.), adopts the genus but also 

 unites thereunder the genera Xi2)hocella, Gray, Callicella, Gray, and Fanellia, Gray, 

 the latter founded on Verrill's description of an axis and placed by Gray in his family 

 of the Primnoidse. 



Studer's diagnosis runs : — Stem ramified, mostly in one plane, the club-shaped calyces 

 are generally scattered on the stem, but on the branches they are in whorls of eight to 

 ten. The calyx scales are more or less fan-shaped, warty, with ribs arranged fan-like, 

 which on the upper edge project as spines. 



The genus Caligorgia is here retained in Studer's sense, and as Dr. Gray intended 

 to use the Greek koKti (pulchra) and not KokXoi (pulcher), the spelling has been altered. 



In Caligorgia the stem is upright, ramified mostly in one plane, but it is never dicho- 

 tomous. The axis is horny, calcareous, rigid, whitish, and ascends from a flat calcareous 

 base which spreads over foreign bodies. The axis is for the most part compressed in the 

 same plane as that in which the branches expand, sometimes completely flattened. The 

 main stem gives off" smaller and larger branches on either side, the latter frequently of 

 the stoutness of the main stem, these either remain simple or may again give ofi" twigs. 

 The branches and twigs always come ofi" alternately on both sides of the stem, and 

 mostly stand at sharp angles to their support. 



Stem and branches are covered with polyp calyces, which are irregularly placed on the 

 thicker parts of the stem and on the branches ; on the thinner branches and twigs they 

 are arranged in whorls, which appear to be always composed of more than three cells. 

 The calyces are cylindrical to club-shaped, with a thickened mouth portion, and in repose 

 and death are bent inwards towards the stem. 



The ccenenchyma contains two layers of spicules, an outer layer of larger, warty, mostly 

 small, almost spindle-shaped and often bent spicules, which lie close together, and a lower 

 layer of smaller, but similarly formed, calcareous bodies. The calyces are distinctly bi- 

 lateral, their backs and sides are covered with tUe-like, overlapping scales, which mostly 

 form four longitudinal rows, the ventral part is naked, only the edge of the calyx 



