152 " THETIS " SCIBNTIFIC RESULTS. 



tendency to form clubbed ends. Fui thermore, the spicules on the 

 tentacles are not arranged in a double row "en chevron." The 

 spindles of the corte-K are very much larger than in D. mdrima ; 

 the star.s and irregular spiny bodies of tlie hase are similar iu 

 both species, but the canal-walls in our specimens do not show 

 any of the numerous, disc-shaped concretions characteristic of D. 

 maxima. 



Order III. PSEUDAXOXIA, G.i-ouKoch. 

 Family MELITODIDAE. 



Genus M O P S E L L A, Gray. 

 MO PS ELL A CLAVIGERA, Ridley. 

 (Plate Ixviii., fis;. 9.') 



Stations 34, 40, 42 and 48. 



Mopsella davigera, Ridley, Report ZooL Coll. H.M.S. " Alert," 

 1884, p. 360, pi. xxxvii., fig. b. pi. xxxvii., figs. a-a'". 



The largest specimens have lengths of 18 era., SS-o cm., 30 cm., 

 and 53 cm. respectively. The branching is generally dichutonious 

 and is strictly in one plane. The branches arise from the nodes, 

 which are very markedly swollen. In the largest specimens they 

 have a diameter of as much as 18 mm. There is no anastomosis. 



The polyps are chiefly confined to one surface, over which they 

 are disposed irregularly in slightly projecting verrucse. Into these 

 the polyps are in the most cases retracted. The polj'p armature 

 consists of eight triangular points of three or four couveiging 

 pairs of delicate spindles ; below these are about two rows of 

 similar spicules disposed horizontally. A double row of minute 

 spicules, " en chevron," occurs along the middle line of each 

 tentacle. 



The spicules of the cceneiichyma are exactly like those 

 described by Ridley, i.e. — (I) orange-coloured fusiform shapes, 

 rather coarsel}' tuberculate, swollen, tapering, with occasional 

 " Hlattkenlen" at one end— -18 x -034 mm.; -15 x 035 mm. (2) 

 "Blattkeulen" of lemon-yellow colour, in shape like small pointed 

 tiowels, with a short handle, and a blade formed of about two 

 lancet shaped lamiiije — -076 x 034 mm. ; 051 x OS? mm ; 042 

 x 025. 



With regard to the distribution of the ccencmhyma spicules, 

 it may be remarked that the orange-coloured spindles generally 



