238 



THE VOYAGE OF H.M.S. CHALLENGER. 



Tertiary beds of the Continent may really belong to this genus. Meneghini has indeed 

 suggested that two forms of joint found in the Italian Tertiaries are those of Bathycrinus:^ 

 but there is no evidence either for or against this idea. For the lower stem-joints of 

 Bathycrinus are indistinguishable from the non-cirriferous joints of Rhizocrinus, though 

 the differences between the immature joints of the upper part of the stem may be readily 

 recognised in the two genera. 



Key to the Species of Bathycrinus herein Described. 



I. The lower part of the radial funnel much constricted, .... 



II. The radial funnel slopes uniformly downwards from the upper to the lower edge. 



a. Calyx constricted at the basiradial suture. Basal ring scarcely wider 



above than below. Arm-joints smooth, .... 



h. The slope of the radials is continued on to the basal ring, which is wider 



above than below. Arm-joints overlap, .... 



1. Campbellianus. 



2. Aldrichianus. 



3. Gracilis. 



1. Bathycrinus campbellianus, n. sp. (PI. Vila. figs. 22, 23; PI. VIII. ; woodcut, fig. 15). 



Bathycrinus aldricManus, Wyv. Thoms. (pars), Journ. Linn. Soc. Lond. (Zool.), (1876), vol. xiii., 

 1878, pp. 47-51, fig. 1 ; The Atlantic, 1877, vol. ii. pp. 92-95, fig. 23. 



Dimensions. 



Description of an Individual. — The radial funnel widens slightly from below upwards 

 to just beneath its equator, where it expands considerably, owing to the dorsal surface of 

 the radials suddenly becoming much more convex. The rim of the funnel is thus drawn 

 out into five curved edges in which the second radials rest. They are trapezoidal in 

 form, widen from below upwards, and have a strong medio-dorsal convexity which starts 

 from the whole width of the lower edge and narrows rapidly till just beneath the dorsal 

 edge, whence it is continued on the axiUary. The lateral portions of the surfaces of both 

 joints are flattened. The axillaries are shorter than the second radials, but wide and 

 barely pentagonal in form, with a medio-dorsal ridge which forks at its proximal end and 

 is continued on to the arm-bases, where it soon disappears. The flattened lateral portions 



' Processi Verbali, Soc. Tosc. di Sci. Nat., 7 Luglio 1878, p. xxxii. 



