237 



PLATE LXXVII. 



RAPHIODESMA LINGUA, Bowerbanfc. 



Hymeniacidon lingua, Bowerbank. Mon. Brit. Spongiada3 



vol. ii, p. 187, and vol. i, pi. vi, figs. 

 144147, also pi. xviii, fig. 297; 

 and vol. iii, pi. xlvii, fig. 8. 



Fig. 1. A fine and very perfect specimen of the 

 sponge from Shetland in its dried state. Natural 

 size. 



Fig. 2. Represents one of the skeleton spicula. 

 X 150 linear. 



Fig. 3. One of the tension spicula. X 320 linear. 



Fig. 4. A large dentato-palmate, inequi-auchorate 

 spicnlum from one of the rosette- shaped groups on the 

 inner surface of the dermal membrane. X 250 linear. 



~Fig, 5. One of the smaller-sized spicula of the same 

 description of form as that represented by fig. 4, 

 They are never congregated in rosette-shaped groups, 

 but 'are abundantly dispersed on the inner surface of 

 the dermal membrane. X 250 linear. 



Fig. g, A group of simple and contort, bihamate 

 spicula. They are very abundantly dispersed on the 

 membranous tissues. X 250 linear. 



For an account of the growth and development of 

 the large dentato-palmate, inequi-anchorate, retentive 

 spicula I must refer the reader to vol. i, p. 48, Plate 

 vi, figs. 144 147, of ' Mon. Brit. Spongiadre,' and to 

 p. 49, Plate xviiii, fig. 297, in the same volume for a 

 description and figure of their congregation in rosette- 

 formed groups. 



In my first description of this sponge I stated that 

 the large inequi-anchorate spicula are " congregated at 

 distant intervals in radiating circles." Subsequent re 



