a System of the Calcareous Sponges. 183 



with repeatedly interlaced anastomosing branches, and with 

 rudimentary retromorphosed persons, the rudimentary stoma- 

 chal cavities of which open in groups through common mouth- 

 apertures. 



Genus 18. *Taerus, nov. gen. 



Gen. char. Canals internally simple, smooth, with a plain 

 entoderm, without papillae or internal partitions. Five species. 



85. * T. c?ewsws, H. Australia. 



86. T. guancha^ H. iGuancha blanca, var. D, M.-M.). 



Lanzarote (M.-M.). 



87. T. reticulatus^ H. {Nardoa reticulatum, var., O. S.). 



Dalmatia (O. S.). 



88. T. lahgrinthus, H. {Nardoa labyrinthus, 0. S.). Lesina 



(O.S.). 



89. T. spongiosics, H. {Nardoa spongiosa^ KoU.). Nice 



(Eberth). 



Genus 19. *Tarroma, nov. gen. 



Gen. char. Canal-walls internally villous, densely clothed 

 with projecting papillai (outgrowths of the entoderm). Three 

 species. 



90. T. canariense^'H. {Nardoa canariensisyM-.-M..). Lanza- 



rote (M.-M.). 



91. T. ruhncm, II. {Nardoa rubra, M.-M.). Lanzarote 



(M.-M.). 



92. T. sulphureujn, H. {Nardoa sulphurea, M.-M.). Lan- 



zarote (M.-M.). 



Genus 20. Clathrina, Gray. 



Gen. char. Canals cliambered internally, i. e. broken up by 

 irregular partitions (lamellar outgrowths of the entoderm) into 

 numerous intercommunicating chambers, in which the embryos 

 occur. Two species. 



93. C. sulphurea, Gray {Grantia clathruSf 0. S.). Sebe- 



nico(O.S.). 



94. *0. loculosa, H. Australia. 



Family VII. Sycodendrida, H. 



Character. The mature calcareous sponge forms a stock 

 with developed persons, each of which possesses a mouth- 

 opening, and of which the stomachal walls are traversed by 

 regular radial canals (radial tubes), as in the Sycarida. 



