20 Spong. 
XVII. SPONGIiE. 
Family Plakinim:. 
Plakinidce , family defined, to include genera Plakinastrella , Plakina , 
Plakortis, Corticium , and Thrombus ; Lendenfeld (27) p. 118. 
Plakina F. E. S., genus defined, with diagnosis of 4 spp. ; Lendenfeld (27) 
pp. 119-121. 
Plakinastrella F. E. S., genus defined, with diagnosis of 1 sp. ; Lendenfeld 
( 27) pp. 118 & 119. 
Plakortis F. E. S., genus defined, with diagnosis of 1 sp. ; Lendenfeld (27) 
p. 121. 
Sub-order OLIGOSILICINA. 
Family CHONDROSiDiE. 
Chondrosia reniformis Ndo., physiology; Cotte (9). 
(b) Order TETRACTINELLIDA. 
(1) Sub-order CHORISTIDA. 
Classification of the Tetractinellida (Choristida) ; Schrammen (46) pp. 
16-19. 
Tribe SIGMATOPHORA. 
Sigmatqphora definition; Lendenfeld (27) p. 15. 
Family Tetillidce. 
Tetillidoe i definition of family, to contain the genera Tetilla, Tethya , and 
Cinachyra ; Lendenfeld (27) p. 16. 
Cinachyra Soil., genus defined, placed in the family Tetillidce , with diagnoses 
of 8 spp. ; Lendenfeld (27) pp. 26-28 & pt. 151. 
Craniella 0. S., see Tethya. C. lens 0. S. and C. lentiformis Thiele, see 
Tethyopsilla. 
Proteleia truncata for Tetilla truncata Tops. ; Lendenfeld (27) p. 29. 
Tethya Lam. = Craniella 0. S., genus defined, placed in the family Tetillidce , 
with diagnoses of 8 spp., pp. 23-25 ; T. oscari nom. nov. for Craniella 
schmidtii Soli. p. 25 : Lendenfeld (27). 
Tethyopsilla Ldf., genus defined, with diagnoses of 7 spp., pp. 30-32; 
f. lens for Craniella lens 0. S., p. 32; T. lentiformis for Craniella 
lentiformis Thiele, p. 31 ; T. pedifera for Tetilla pedifera Soil., p. 30 : 
Lendenfeld (27). 
Tethyopsillidce , definition of the family, to include the genera Tethyopsilla 
and Proteleia ; Lendenfeld (27) p. 29. 
Tetilla O. S., definition of genus and diagnoses of the 19 spp. ; Lendenfeld 
(27) p. 16. T. casula (Ortr.), note on ; Kirkpatrick (25) p. 178. 
T. lindgreni nom. nov. for T. ternatensis Lindgren non Kieschnick ; 
Lendenfeld (27) p. 18. T. pedifera Soil., see Tethyopsilla. T. trun- 
cata Tops., see Proteleia. 
Tribe ASTROPHORA. 
Astrophordy definition ; Lendenfeld (27) p, 32. 
