472 



NATURE 



retractile processes, disposed in a single row all along 



[March 18, 18S0 



Fig. 5. — Cryodora spongiosa, The'el. Dorsal surface. 



Integument spongy without 



each of its ambulacra, 

 calcareous deposits. 

 C. spongiosa, n.sp. 



Lalmogone n.g. (Fig. 6) (Kahfia, depths of the sea). 

 Back highly convex ; ventral surface slightly so. Mouth 

 anterior, terminal, subventral ; anus posterior, terminal, 

 slightly dorsal. Tentacles fifteen. The lateral ambulacra 

 of the trivium with large, not retractile, only a little 

 contractile pedicels, disposed in a single row all along 

 each side of the ventral surface. The odd ambulacrum 



Fig. 6.— Ltetmegoiic wyvillc-thomsmi, The'el. Side view. 



naked. Bivium with highly elongated, flexible, cylindrical, 

 not retractile processes, disposed in a single row all along 

 each of its ambulacra. Integument with numerous wheel- 

 shaped plates and other calcareous secretions. 

 L. ivyvillc-thomsoni, n.sp. ; L. violacea, n.sp. 



Ilyodamon (Fig. 7), n.g. (l\vs, ooze, 8aipa>v, spiiit). 



Back highly convex ; ventral surface nearly flat. Mouth 

 anterior, almost ventral ; anus posterior, terminal, sub- 

 dorsal. Tentacles fifteen. The lateral ambulacra of the 

 triyium with large, not retractile pedicels, apparently 

 disposed in a double row all along each side of the ventral 

 surface. The odd ambulacrum naked. Bivium with a 

 crowded scries of very numerous, completely retractile, 

 slender, rather long processes, disposed in three or four 

 irregular close-set rows all along each of its ambulacra. 

 Integument with numerous wheel-shaped plates and 

 dichotomously branched bodies. 



L. maculatus, n.sp. 



Achlyonkc n.g. (Fig. 8) (a K Us, darkness). 



Back highly convex ; ventral surface flat or almost 



concave. Mouth anterior, ventral; anus posterior, 



dorsal. Tentacles twelve. The lateral ambulacra of the 



trivium with more or less retractile pedicels, disposed in 



Fib. 7. Fig. S. 



Fig. 7 —IlycdamoH maculatus. The'el. Ventral surface. Fig. 8. — 

 Achlyonice e:alcari-a, The'el Ventral surface. 



a single row all along each side of the ventral surface. 

 The odd ambulacrum naked. Bivium with a few very 

 soft and flexible processes in its anterior part alone. 

 Integument thick, spongy, destitute of calcareous deposits. 

 A. ccalcarea, n.sp. 



Elpidia, The'el (Fig. 9) (AirtV, hope). 

 "Memoire sur 1'Elpidia," K. Sv. Vct.-Akad. Hatldl., 

 Bd. 14, No. 8, 1877. 

 Body ovate, more or less elongated, sometimes cylin- 

 drical. Mouth anterior, terminal, or subventral, anus 

 posterior, terminal, subventral, or subdorsal. Tentacles 

 ten. The lateral ambulacra of the trivium with large, 

 slightly retractile pedicels, disposed in a single row along 



Fig. q.—Elfidia globosa, The'el. Side 



each side of the ventral surface. The odd ambulacrum 

 naked. Bivium with one or a few pairs of often very 

 elongated, not retractile processes on each of its ambulacra, 

 or with only a few more or less rudimental ones in its 

 anterior part. Integument with spicula of various 

 shapes. 



E. mollis, n.sp. 



E. nana, n.sp. 



E. papulosa, n.sp. E. elongate, 



E. glacialis, The'el 

 E. verrucosa, n.sp. 

 E. murrayi, n.sp. 

 n. sp. 



Irpa, K. and D. (Fig. 10) (from the Norse mythology). 

 Body nearly cylindrical, bilateral. Mouth nearly 

 central, anal opening terminal. Ten short, thick, digitate 

 tentacles. Along the sides of the body nine pairs of long 





