NOTES ON A DEEP-SEA ECHIUEOID. 139 



radially across the .whole thickness. Besides these fibrils, 

 the cutis contains small, mostly round, and rather sparsely 

 dispersed spaces {hic), each of which encloses a very small 

 cell (c). Although owing- to the imperfect preservation I 

 have been unable to make out exactly the minnte structure 

 of these corpuscle-like cells, yet, as far as my preparations 

 show, the latter are indubitably nucleated, and are provided 

 with a few slender processes i-eaching the sides of the 

 enclosing capsule. These cells are no doubt similar to the 

 cutis-corpuscles known in the cutis of Hamingia arctica 

 (Danielsen and Koren, and Horst) ; in this case, however, 

 the cells are not embedded in any special cavity. I am not 

 able at present to decide whether these lacuna-spaces are or 

 are not largely artefacts due to strong contraction of the 

 coi'puscles themselves. 



The epidermis is comparatively thin, consisting of a single 

 layer of cells, cubical or subcylindrical in shape, and of 

 unicellular glands of various sizes. Rather curiously, the 

 cuticle, which is clearly differentiated in Hainingia arctica, 

 is not found as a distinct layer or, at least, cannot be distin- 

 guished from the epidermal epithelium. Whereas iu smooth 

 parts of the skin the gland-cells are in general small and only 

 sparsely distributed, in the papillai they {p. gl.) are so con- 

 spicuously large and so closely aggregated that the real state 

 of their arrangement is often hardly perceptible. The 

 papillary glands are very variable in size and shape and show 

 different structures, probably according to states of the 

 secretory activity of the cells ; hence the cell contents, which 

 stain deeply with luematoxyliu, may be seen as a compact 

 mass, or as an aggregation of minute granules, or as a more 

 lightly stained mass showing a reticular structure. 



No pigment-granules are recognisable in any of dermal 

 tissues. 



In connection Avith the skin, the ventral hooks may be 

 described. They are unusually numerous, that is, eight 

 instead of two. As in Bonellia miyajimai,^ hitherto the 



^ Ikeda, I., " On Three New and Remarkable SiDecies of Ecliiuroids 



