m 



PLATE LXXVII. 



Raphiodesma lingua, Boiverban/c. 



Hijmcuiacidon lingua, Bowerlmnk. Mon. Brit. Spongiada;> 

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

 144—147, 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 tlie skeleton spicula. 

 X 150 linear. 



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



Fig. 4. — A large dentate-palmate, inequi-anchorate 

 spiculum 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 1)}^ fig. 4. 

 They are never congregated in rosette-shaped groups, 

 but are abundantly dispersed on the inner surface of 

 the dermal membrane. X 260 linear. 



Fig. 6. — A group of simple and contort, bihamate 

 spicula. They are very abundantly dispersed on the 

 membranous tissues. X 250 hnear. 



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. Spougiadfe,' and to 

 2?. 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- 



