133 



PLATE LI1. 



ISODICTYA PALMATA, Bowerbank. 



Vol. ii, p. 311, ' Mon. Brit. Spongiadse.' 



Fig. 1. Represents the specimen of this species 

 designated as the " Mermaid's Glove " sponge, dredged 

 at the Orkney Islands, by Mr. McAndrew, in 1851. 

 Half the natural size. 



Fig. 2. A small portion of the reticulated skeleton 

 of the sponge, illustrating its structural peculiarities. 

 X 80 linear. 



Figs. 3, 4, 5. Three of the remarkable equi-ancho- 

 rate, retentive spicula, with flexuous terminations. 

 X 666 linear. 



Fig. 6. One of the minute equi-anchorate retentive 

 spicula, with siliceo-membranous terminations. X 666 

 linear. 



Fig. 7. One of the skeleton spicula. 



