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



long diacts with rough rounded extremities are accordingly all the more abundant. 

 These are here, moreover, not so uniformly disposed in a longitudinal direction as in 

 thinner stalks, but occur with some irregularity, though for the most part longitudinally. 

 These principalia are extensively united into a firm framework by means of synapticula. 

 It is to be regretted that the dermal skeleton of the stalk has been rubbed oif, and also 

 that the inner lining of the cavity of the stalk is no longer intact. 



Caulophacus elegans, n. sp. (PL XXV.; PI. XXVI. figs. 1-3). 



A second species of Caulophacus was trawled to the east of Japan (Station 241, lat. 

 35° 41' N., long. 157° 42' E.) from 2300 fathoms, on red clay ground. Three specimens 

 were collected, two of them small forms with short imperfect stalks. One of these, as 

 figured on PL XXVI. fig. 1, show^s a marked resemblance to Caulophacus latus. The 

 straight, round, hollow stalk, 1"5 mm. in diameter, is continued by a trumpet-like expan- 

 sion into the slightly curved superior extremity with a convexo-concave circular disc, with 

 somewhat overhanging margins. In the specimen figured the diameter of the disc 

 measures almost 2 cm., and the greatest thickness 5 mm. Another much injured 

 specimen is somewhat smaller. A tolerably distinct form is figured in PL XXV. fig. 1, 

 from a somewhat larger third specimen. The hollow stalk is somewhat bent at the end, 

 and though on the whole straight, is slightly curved here and there in an undulating 

 manner. It measures 3 mm. in diameter, and bears terminally a biconvex lens-shaped 

 disc, 4 cm. in breadth and r5 cm. in thickness, with a somewhat downwardly bent 

 margin. In spite of some superficial ii'regularities on the upper side and several 

 shallow folds below, both surfaces appear on the whole to be uniformly arched, though the 

 upper is the more convex. The stalk, though broken off" below, attains a length of 9 cm. 

 I am inclined to beheve that the piece of stalk which was brought up along with the 

 former, and which exhibits a similar structure and a length of 15 cm. (PL XXV. fig. 2), 

 really belonged to the kame specimen, and formed the inferior extremity of the stalk, 

 which would accordingly measure 24 cm. in length. 



As in Caulophacus latus, the principalia consist of strong, regular, smooth hexacts, 

 and long diacts with rounded, more or less rough, extremities. These have an isolated 

 or a bundle-like distribution. Each of the rays of the hexacts exhibits a bulging swelling 

 in the middle, and a rounded terminal point. The diacts usually exhibit a central 

 axial canal intersection, but as a rule there are no knob-like protuberances or ring-like 

 swellings to represent the remnants of abortive rays. Between the principalia the same 

 small regular pronged hexacts, with marginally pronged, arched, terminal plates, occur in 

 great numbers, resembling those which we have akeady become acquainted with in 

 the other species, and in Balanites pipetta (PL XXIV. fig. 7). Simple division of a ray, 

 as shown in PI. XXV. fig. 7, may occasionally be observed. On the other hand. 



