112 



TH. MORTENSEN, 



(Schwed. Siidpolar-Exp. 



Fig. 17. Globiferous pedicellaria of Loxechinus albus. s %- 

 » 18. Sphaeridia of Sterechinus Agassizii. 15 °/i. 



» 19. Globiferous pedicellaria, large form, of Notechinus magellanicus. (Comp. Fig. 3.) 

 5 %. 



Plate XVII. 



Fig. 1. Part of the abactinal side, with the apical system of Plexechinus Nordenskjoldi. 



The upper plates of the frontal ambulacrum were not quite distinct. 8 /i. 

 » 2. Part of the actinal side of Plexechinus Nordenskjoldi. s /x. 



3. Plexechinus Nordenskjoldi. Side view. 2 / z . I 

 » 4. » » Abactinal side. 2 /i.| Figs. 3 — 5 same specimen. 



» 5. » Actinal » »/x.l 



» 6. » » Abactinal » 2 - 5 A-j 



» 7. » » Actinal » 2 " s /i-f Figs. 6 — 8 same specimen. 



» 8. » » Side view. 2,5 /i. J 



9. Part of the abactinal side, with the apical system, of a young Abatus cavemosus, 

 1.9 mm. length. 5 %- 



» 10. Amphipneustes Koehleri, young specimen from the marsupium; 2 mm. length. 



Same specimen as Fig. 11. 2 %- 

 » 11. Amphipneustes Koehleri. Same specimen as Fig. 10. Actinal side. 2 %. 



Plate XVIII. 



Fig. 1. Amphipneustes Koehleri; young specimen, 2 mm. length. Actinal side. 27 /i. 

 >; 2. » » Same specimen as Fig. r. Abactinal side. 27 1 1. 



» 3. Abatus cavemosus; young specimen, 1.5 mm. length, from the marsupium. Actinal 



side. * 5 /i- 



» 4. » » same specimen as Fig. 3. Abactinal side. 45 /i. 



Figs. 5 — 12. Plexechinus Nordenskjoldi. 

 » 5. Valve of ophicephalous pedicellaria. 2 °%. 



» 6. » » tridentate » from the inside. (Comp. Fig. 11.) I7 %- 



» 7. » » triphyllous » zoo /i- 



» 8. Sphaeridia. I7 %. 



» 9. Secondary spine. " s /i- 



» 10. Filament of actinal tubefoot. The pigment omitted. I7 °/i. 



» 11. Valve of tridentate pedicellaria, side view. (Comp. Fig. 6.) I7 %- 



» 12. Ophicephalous pedicellaria. II5 /i. 



Plate XIX. 



Fig. 1. Tridentate (bivalve) pedicellaria of Amphipneustes Lorioli. 35 /i. 

 » 2. » » » , small form, of Amphipneustes Lorioli. 3S /i. 



» 3. Valve of globiferous pedicellaria of Amphipneustes Koehleri. Side view. (Comp. 



Fig. 20.) 7%. 

 » 4. Sphaeridia of Amphipneustes Koehleri. "%. 



