PENNATULIDA DREDGED BY H.M.S. "TRITON." 133 



suggested # that the lower fracture, which usually occurs about the junction of 

 stalk and rachis, i.e., about the point of emergence from the mud of the sea 

 bottom, is caused by the dredge at the moment of capture ; while the upper 

 fracture is almost certainly effected quite independently of the dredge, and is 

 perhaps due to the tops being browsed on as food by other animals. The 

 great brittleness of the calcareous stem probably accounts for the readiness 

 with which the specimens become broken, and the fact that of the three 

 specimens of V. tuberculata, the one brought up by the dredge is broken at 

 both ends, while the two taken with the trawl have their lower ends entire, speaks 

 strongly in favour of the correctness of the first part of the above explanation. 

 The measurements of the three specimens are as follows : — 







A. 



B. 



C. 



Total length, , 

 Rachis, . . 





Upper end imperfect. 

 68 mm. 

 53 



Upper end imperfect. 

 36-4 mm. 

 28-4 



Both ends lost. 

 46 mm. 

 46 



Stalk, 





15 



8 



... 



Diameter of rachis, 





. 0-5 to 2-6 



0-4 to 2-1 



0-52 



„ stalk, 





2-1 



11 



... 



„ stem, 





0-4 



0-38 



0-4 



No. of polyps per leaf, 

 Length of polyp, 

 „ tentacle, 





3 



8 

 1 



3 



3 

 11 



1-4 



Distance of polyps apart 

 Diameter of spermatospb 



(grea 

 eres, 



test), 3 



0-38 



... 



3-1 



Family 2. Stylatulidae. 



Diibenia, Kor. and Dan. 

 Diibenia dbyssicola var. smaragdina (Kor. and Dan.). (PI. XXIII. figs. 17-21.) 



A single fragment of this species was obtained from Station 11 at a depth 

 of 555 fathoms. The specimen, which is imperfect at both ends, and has a total 

 length of 61 mm., is represented from the ventral surface three times the natural 

 size in PI. XXIII. fig. 17 ; while figs. 18 and 19 represent on a larger scale 

 portions of the rachis as seen from the lateral and dorsal surfaces respectively. 



Inasmuch as the sole description that has yet appeared of this very beautiful 

 form is the extremely short and imperfect account given by Koren and 

 Danielssen,! I have thought it well to investigate and describe the " Triton " 

 specimen as fully as could be done without injury to it. 



The rachis (figs. 17, 18, and 19) is cylindrical, and only slightly exceeds in 

 diameter the cylindrical stem by which it is traversed throughout its length. 

 At the upper end of the specimen the. stem projects bare for a length of about 



* Vide Report on the Oban Pennatulida, by A. M. Marshall and W. P. Marshall, 1882, pp. 57-60. 

 f Fauna littoral is Norvegim, part iii. p. 26, and pi. x. figs. 7 and 8, 1877. 



