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



Calcareous corpuscles are only found very scantily in the muscular layer in the 

 lowest parts of the stalk. They are small oblong bodies of 7 to 22 [x, which are 

 often united four together so as to form small star-like figures. 



The axis is round, and of the common lameUiferous and fibrous structure. Its 

 radiating fibres are very numerous, hut short. 



The measurements of nine well-preserved specimens of Antlioptilum thomsoni are 

 as follow : — 



A. B. C. D. E. r. G. H. I. 



Length of the whole polypidom, 



Length of the stalk, 



Breadth of its enlargement, 



Breadth of the pen. 



Length of the polyps with the 



tentacles, 

 Length of their tentacles, 

 Breadth of the rachis, . 



Habitat. — Station 320, Atlantic Ocean, south of Buenos Ayres, lat. 37° 17' S., long. 

 53° 12' W. Depth, 600 fathoms. Bottom temperature, 2°-7 C. Hard ground. 

 February 14, 1876. 



2. Antlioptilum murrayi, n. sp. (PL VI. figs. 19-21). 



General appearance of Anthoptihm thomsoni, smaller, with smaller and less numerous 

 polyps, two to three in each row. Polyps all sessile, widely separated from each other. 

 Eachis without polyps in the middle line on both sides. Zooids more distant than in the 

 last species. 



Stalk long, slender, without distinct enlargement. 



Polyps disposed in oblique rows of two to three, seldom four, on both sides of the 

 rachis, which arrangement is not very apparent everywhere, all Avell separated from their 

 neio-hbours, and the dorsal smaller than the ventral, with tentacles often far surpassing in 

 length the bodies of the polyps. 



The zooids cover the whole rachis between the polyps, and leave only the middle j^art 

 of its ventral and dorsal aspect free. On the ventral side the zooids are situated on the 

 margin and form not more than one single row, which is even interrupted here and there 

 on the ventral side of the lowest polyps, whilst on the dorsal aspect they go nearer the 

 middle line, and leave only a small part of the rachis free. These zooids, which in no 

 case are situated on the bodies of the polyps as in A. thomsoni, measure 0"34 to 0'40 mm. 

 in width, and their distance from one another is equal to, or greater than, their diameter. 

 They have all two mesenteric filaments. The colour of the polypidom is pale red, the 

 polyps brown, while the rachis and stalk are usually colourless, and present only here 

 and there a light brown or pale rosy tint. 



