670 " THETIS " SCIENTIFIC RESULTS. 



tendency to form clubbed ends. Fuithermore, the spicules on the 

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

 spindles of the cortex are very much larger than in D. maxima ; 

 the stars and irregular spiny bodies of the base are similar in 

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

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

 maxima. 



Order TIL PSEUDAXONIA, G. von Koch. 



Family MELITODIDAE. 



Genus MOPSELLA, Gray. 



MOPS ELLA CLAVIGERA, RidUy. 



(Plate Ixviii., fig. 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 cm., 23-5 cm., 30 cm., 

 and 53 cm. respectively. The branching is generally dichotonious, 

 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 polyp armature 

 consists of eight triangular points of three or four converging 

 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 coenenchyma are exactly like those 

 described by Ridley, i.e. — (1) orange-coloured fusiform shapes, . 

 rather coarsely tuberculate, swollen, tapering, with occasional 

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

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

 trowels, Avith a short handle, and a blade formed of about two 

 lancet shaped laminae — -07 6 x -034 mm. ; '051 x -032 mm. ; -042 

 x -025. 



With regard to the distribution of the coenenchyma spicules, 

 it may be remarked that the orange-coloured spindles generally 



