PLATE XVI. 



Fig-. 80. Piridium longiapinxm Jøkg., ■*=7i- Senjcn, ^Vi 1899, — 130 in. Fully developed specimen. Lateral view; the left lateral 

 aix'h (]3j.), with two strong- byspiaes, in front. 



„ 81. Lithomelissa setosa Jøhg., ■'*7i- Henningsvær, *7i 1899, 0—180 m. Young specimen. Dorsal view; tlie spine A in front, 



somewhat to the left (directed downwards). 

 ,, 82. L. setosa Jøkg., ''^Vi- Apical view. 



., 83. L. setosa Jørg., *°°/i. The Herlø Fiord (near Bergen), -^/-^ 1899. Almost fully developed specimen; lateral view. 

 84. L. laticeps Jøeg. n. sp., *^7i- Sea off Røst, "A 1899, 0—900 m. Lateral view. 



b. The same, optical section, showing the main spines. 

 „ So. L. hystrix Jørg., *"7i. Skroven, V2 1899, 0—300 m. 50 \i high and broad. Thorax 36 'i high; cephalis 14 <i high, 25 



l>- broad. Most of the spines broken off. 

 „ 86. Helotholus Mstricosa Jørg. n. sp., ^°7i. Øxsund, '72 1899, 0—300 m. 



a. Inside the shell the long axial divided spine is seen. 



b. Antapical view of the cephalis and the upper part of the thorax (neck stricture). 4 spines are seen. 

 ,, 87. H. Mstricosa Jørg., ^'*7i- From the same locality. Young specimen. 



b. Portion of a broken shell, showing the protruding ventral, sagittal spine. 

 „ 88. H. Mstricosa Jørg., ^=^'U. Ofoten II, 72 1899, 0—100 m. Apical view. Diameter of the thorax 94 ij., of the cephalis 27 [i.. 



Pores very uneven, from 5 to 20 |j.. 

 „ 89. DictyopMmus Mstricosus Jørg. n. sp., -'571. Sea off Røst, --/a 1899, 0—900 m. Shell 68 'j. high, 85 broad; cephahs 22 |t 



hig-h, 84 broad. Pores uneven, from 9 n to very small, not considerably smaller on the cephalis. 



b. The same; optical section, showing 4 main spines. The three swelling-s, mentioned \inder Lithomelissa srtosa (above p. 127) 

 and other species, are distinctly seen. 

 ., 90. Litharachnium tentorium. Hck. Sea north of Shetland. 63" 36' n., 0" 32'_ e., "A 1903 (S/S Michael Sars). 



a. The entire shell of a fully developed specimen, ="7]. 



b. Upper (conical) part of the shell, ■'^7i. 



c— e. Pores and parts of the network, ''«7i ; c from below the broken part of the shell, e the largest pores of the cone, 

 above the beginning intermediate ribs, d farther down on the cone, where intermediate ribs appear. 

 „ 91. L. tentorium Hck., *^"/\. Skroven, 7* 1899, — 150 m. "^'oung specimen. 



a. Lateral view. 



b. Apical view. The 3 primary meshes in the neck stricture are seen. 



c. A portion of the network near the margin below. 



