PLATE X. 



Flir. 38. Hhuoplegma horeaJc (Cl.) Jpro., -'^^i- 



e. Young specimen with 7 main spines. Diameter of the inner shell 28—30 \i. Sea 40 miles NW of Gaukværø, '"/i 1899, 

 0—700 m. 



f. Young specimen, divergent form with 11 main spines. Henningsvær, ''/i 1899, 0—180 m. 

 ., 39. tiiylodictija tenuispina Jørg. n. sp., ""A. Sea off Røst, "/a 1899, 0—900 m. 



a. In the figure the inner rings are seen, and the connecting inner radial beams which are, however, only shown on the space 

 between the two outer rings. The coarse pores on the median part of the shell and some of the pores on the other 

 portion are also depicted. 



b. The same specimen, optical section, showing the rings and radial beams. 



c. The same in side view, optical section. In the middle the rounded higher portion is seen. Punctiform byspines on both sides. 

 „ 40. S. raftdispina Jørg. n. sp., *'=7i- Sea off Røst, ^Vs 1899, 0—900 m. 



a. Optical section, showing the system of rings and the radial spines. The pores on the outside are shown on a portion of 

 the valve. 



b. The same specimen in side view; optical section. 



., 41. S. aculeaia Jøeg. n. sp., «"/i. Sea off Røst, "I-, 1899, 0-900 m. 



a. The disc from above, with pores and radial spines. The small dark puneta on the surface ai-e the byspines. The inner 

 rings are suggested. 



b. The same specimen; optical section. 



c The same in side view; optical section. 

 ., 42. Phorticium pylonium (Hck.?) Cl., «o/j, T]^e Tys Fiord, -«/s 1899, 0-700 m. 



'''. Schematical iigure, dorsal view, showing in perspective the 3 girdles, perpendicular to each other. The tigure shows only 

 one of these systems of girdles; in reality there are 3 of them. L = the lateral girdle, seen from the (narrow) side; 

 T = the transverse girdle, S ■= the sagittal one. In the middle of the latter an inner lateral girdle is developed, 

 parallel to the outer one (is not seen in the figure), in the middle of this inner lateral girdle, an inner transverse one, 

 a. s. 0. For the sake of clearness, the girdles are depicted narrow, and distinctly compressed. 



a. Dorsal view, showing the pores and the outer spines (main- and byspines). 



b. The same specimen, same view, optical section (lateral section). To the right and left the outer latei-al girdle is seen, 

 and parallel to this two innei- ones. 



c. Same specimen, apical view. When the figure is seen from the side, where the number (42 c) is printed, it answers to 

 the fig. a, seen from above. 



d. Same specunen, same view: optical section (= transverse one). The transverse girdle goes around the figure, and is 

 seen from the (narrow) side. Across this girdle the outer sadttal one is seen, and in the inner, the second and third 

 transverse ones. 



