6 A MONOGRAPH OF THE 



packed spicula ; the distal ends of each pedicel sepa- 

 rating and radiating in numerous curved lines, which 

 spread over the inner surface of the dermal membrane, 

 separating and sustaining it at all parts at a consid- 

 erable distance from the central axis of the skeleton. 

 Vol. I, p. 179. 



Type, Ciocalypta penicittus, Bowerbank. Vol. I, Plate 

 XXX, Figs. 360, 361. 



8. Tethea, Lamarck. 



Sponge massive, suborbicular. Skeleton consisting of fas- 

 ciculi of spicula. Fasciculi radiating from a basal or 

 excentrical point to the surface. Intermarginal cavities 

 unsymmetrical, confluent. Propagation by internal 

 or external gemmulation. Vol. I, p. 181. 



Types, Tethea lyncurium, Linnaeus, and T. cranium, Lamarck. 

 Vol. I, Plate XXXI, Fig. 362. 



9. Halicnemia, Bowerbank. 



Skeleton formed of a single superior stratum of spicula 

 radiating from the centre to the circumference of the 

 sponge at about its middle, and of an inferior stratum 

 of spicula distributed without order. Vol. I, p. 184. 



Type, Halicnemia patera, Bowerbank. Plate XXXII, Figs. 

 363, 364. 



10. Dictyocylindrus, Bowerbank. 



Skeleton. Without fibre. Composed of a loosely com- 

 pacted columnar axis of spicula, disposed principally 

 in the direction of the line of the axial column, from 

 which a peripheral system of long single or fasciculated 



