a System of the Calcareous Sponges. 183 



with repeatedly interlaecd anastomosing branches, and with 

 rudiinentary rctromorpliosed persons, the rudimentary stoma- 

 chal cavities of which open in groups through common mouth- 

 apertures. 



Genus 18. *Taruus, no v. gen. 



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

 entoderm, without papilla) or internal partitions. Five species. 



85. * 2". densus, II. Australia. 



86. T. (/iiancha, II. {Guancha blanca, var. D, M.-M.). 



Lanzarote (M.-M.). 



87. T. rcticuhitus, II. [Nardoa rettculatum, var., O. S.). 



Dalmatia (O. S.). 

 SS. 2\ lal>i/rin(hus, II. {Nardoa lahyrinthus, O. S.). Lesina 



(O. 8.). ^ 

 8y. T. sjmngiosus, II. [Nardoa sjjongiosa, Koll.). Nice 



(Eberth). 



Genus 19. *Tx\.rroma, nov. gen. 



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

 with projecting papilla3 (outgrowths of the entoderm). Three 

 species. 



90. T. ranan'cnse, II. {Nardoa canariensis, M.-M.). Lanza- 



rote (M.-M.). 



91. T. riibrum, H. {Nardoa rubra, M.-M.). Lanzarote 

 ^ (M.-M.). 



92. T. suljihureum, II. {Nardoa sulphurea, M.-M.). Lan- 



zarote (M.-M.). 



Genus 20. Clathrina, Gray. 



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

 irregular partitions (lamellar outgrowths of the entoderm) into 

 numerous interconnnunicating chambers, in which the embryos 

 occur. Two species. 



93. C. sulj)hureaj Gray {Grantia clathrusy O. S.). Sebe- 



nico (0. S.). 



94. * C. locuhsa, II. 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. 



