112 TH. MORTENSEN, (Schwed. Südpolar-Exp. 



Fig. 17. Globiferous pedicellaria of Loxechinus albus. ^°ji. 



» 18. Sphîeridia of Sterechinus Agassizii. "Jo/j. 



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



Plate XVII. 



Fig. I. Part of the abactinal side, with the apical system of Plexechiniis Nordaiskjohii. 



The upper plates of the frontal ambulacrum were not quite distinct. *, i. 

 » 2. Part of the actinal side of Plexechiniis Nordenskjoldi. ^/i. 

 » 3. Plcxcdiinus Nordenskjoldi. Side view, ^/i 1 



» 4. » » Abactinal side, ^/i./ Figs. 3 — 5 same .specimen. 



» 5. » » Actinal » ^/i.l 



» 6. » » Abactinal » ^''/i.) 



» 7. » » Actinal » '^■^/i.!' Figs. 6 — 8 same specimen. 



» 8. » » Side view. ^'S/i. J 



» g. Part of the abactinal side, with the a]:iical system, of a young Ahalus cavernosus, 



1.9 mm. length. 5°/i. 

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



Same specimen as Fig. 11. '"'/i. 

 » II. Amphipneustes Koehleri. Same specimen as Fig. 10. Actinal side. "°/i. 



Plate XVIII. 



Fig. I. Amphipneustes Koehleri; young specimen, 2 mm. length. Actinal side. °7/j. 

 » 2. » s Same specimen as Fig. i. Abactinal side. ^^Ii. 



>> 3. Abat us cavernosus ; young specimen, 1.5 mm. length, from the mar.sujjium. Actinal 



side. •t5/i- 

 » 4. » » same specimen as Fig. 3. Abactinal side. ^^U. 



Figs. 5 — 12. Plexechinus Nordenskjoldi. 



i 5. Valve of ophicephalous pedicellaria. ^°°'i. 



» 6. 3 » tridentate » from the inside. (Comp. Fig. 11.) '^o/j. 



» 7. » » triphyllous » ^°°/i- 



» 8. Sphaeridia. ^^°h. 



» 9. Secondary spine, "'/i. 



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



» II. Valve of tridentate pedicellaria, side view. (Comp. Fig. 6.) ''Vi- 



» 12. Ophicephalous pedicellaria. "^y,. 



Plate XIX. 



Fig. I. Tridentate (bivalve) pedicellaria of Amphipneustes Lorioli. 3S j. 

 » 2. » s » , small form, of Amphipneustes Lorioli. ^s.'j. 



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



Fig. 20.) 7°/,. 

 » 4. Sphaeridia of Amphipneustes Koehleri. "°/i. 



