4 THE VOYAGE OF H.M.S. CHALLENGEE. 



Habitat. — A single specimen from Station 232, south of Yeddo, Japan, lat. 35° 11' 

 N., long. 139° 28' E. Depth, 345 fathoms. Sandy mud. Bottom temperature, 5° C. 

 May 12, 1875. 



Pennatula naresi at first sight somewhat resembles P. grandis, Ehrenberg (P. 

 horealis, Sars, Ptilella grandis, Koren and Danielssen), but on closer inspection the 

 differences are numerous and great. Before entering into this subject, I wish to say that 

 I cannot accept the genus Ptilella of Gray, which has been defined by him as follows : — 

 " Pinnules membranous, broad, rounded, fringed with three close parallel series of short 

 polyp-cells on the edge. Eachis granular on each side behind without any spines." 

 Koren and Danielssen have accepted the genus Ptilella, and define it as follows : — " Very 

 large sea-pens, with large, broad, semilunar fins bearing several rows of polyp-cells. The 

 ventral surface naked. The zooids lateral, extending towards the centre of the dorsal surface. 

 On the ventral margin of the fins strongly developed zooids. The sexual organs in the 

 fins. On the upper part of the stalk a fleshy enlargement. The axis is thick and round, 

 curved downwards in the form of an S, terminating in a hook, while in the upper part it 

 terminates in a volute." With regard to this definition I have to add, (l) that Penna- 

 tula grandis, Ehrb., has very fully developed ventral zooids, which are tolerably well 

 represented in fig. 2 of Sars; and (2) that this species has, also a row of zooids at the 

 doi'sal end of the polypiferous margin of the leaves on the ridge, with which each leaf runs 

 out upon the rachis. Now, if we define, as I have done, the Pennatulidee as sea-pens with 

 well-developed leaves, which bear the zooids principally upon the ventral surface of the 

 rachis ; and the genus Pennatula as a pennatulid the leaves of which are beset in their 

 totality with calcareous needles, whilst these are found only in the polypiferous zone, in 

 the genera Ptilosarcus and Leioptilum, and are totally wanting in Halisceptrum, — 

 Pennatida grandis is a true Pennatula. At all events, I would rather unite the genera 

 Ptilosarcus and Leioptilum with Pennatula than subdivide the Pennatulce on ground so 

 slight as the number of rows of polyp-cells, the size of the enlargement of the stalk, the 

 disposition of the zooids in each group, or even the presence or absence of zooids on the 

 ventral and dorsal margins of the leaves. 



2. Pennatula pearceyi,^ n. sp. (PI. II. fig. 5). 



Small, of a reddish colour, with four to five polyps on the margin of the small 

 lanceolate pinnules. Zooids ventral and lateral, two to four in each set, small, all of 

 the same size. Feather more than double the length of the stem. 



Pinnules thin, transparent, slender, oblic[uely attached to the rachis, 3 mm. broad at 

 their base. Ventral margin of the pinnule straight, dorsal margin with obliquely disposed 

 polyp-ceUs, and thus appearing serrated. Free end of the pinnule formed by one polyp-cell. 



Polyps four to five on the dorsal margin of the pinnule, and two to three small 



^ Named after Mr Frederick Penrcey, an excellent assistant attached to tlie Civilian Staff. 



