REPORT ON THE TETRACTINELLIDA. ix 
PAGE 
VI. APPENDIX II.— MONAXONIDA, ....... 411 
Introduction and Classification, ........ 411-419 
Relation to the Tetractinellida, . . • • . ... . 419-421 
Description of Species, . . . . . . . 421 
Suborder III. Spintharophora, . . . . . . . 421 
Group I. Homosclera, ........ 422 
Family I. Astropeplidse, . . . . . . . 422 
Astropeplus, n. gen., ....... 422-423 
Group II. Heterosclera, ........ 423 
Demus I. Centrospinthara, . . . . . . . 423 
Family I. Axinellidse, . . . . . 423 
Epallax, n. gen., ....... 423-425 
Family II. Dorypleridse, . . . . . . . 425 
Donypleres, n. gen., ....... 426 
Family III. Tethyids, ........ 427 
Tetliya, Lamarck, ....... 427-432 
Demus II. Spiraspinthara, . . . . . . . 432 
Family I. Scolopidse, ........ 432 
Scolopes, n. gen., ....... 432-433 
^ Supplementary Account of Centrospinthara not in Challenger Collection, . . 434-444 
Family I. AxinellidEe, ........ 434 
Hemiasterella, Carter, . . . . . . . 434 
Family II. Dorypleridae, ....... 434 
Dorypleres, ........ 434-435 
Family III. Tethyidse, ........ 435 
Tetliya, ........ 435-441 
Columnites, 0. Schmidt, ...... 441-442 
Magog, n. gen., ........ 442-443 
Xenospongia, Gray, ....... 443-444 
List op Stations at which Spintharophorous Monaxonida have been obtained, 
WITH THE species PROM EACH, ....... 444-445 
VII. SYSTEMATIC INDEX, ........ 447-455 
VIII. INDEX TO AUTHORS, ........ 457 
IX. EXPLANATION OF PLATES. 
X. MAP. 
(ZOOL. CHALL. EXP. — PART LXIII. — 1888.) 
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