59 



PLATE XXIII. 



MiCEOOlONA PICTITIA, Boiverbrmk. 

 Yol. ii, p. 12-i, ' Moil. Brit. SpongiadEe.' 



Fig. 1. — Represents the type-specimen in tlie cabinet 

 of tlie Eev. A. M. Norman. Natural size. 



Fig. 2. — -A sl'celeton spiculum. X 160 linear. 



Fig. 3. — One of the basally-spined, attenuato-acuate, 

 external, defensive spicula. X 160 linear. 



Fig. 4. — One of the entirely spined attenuato-acuate 

 internal, defensive spicula. X 150 linear. 



Fig. 5. — The basal portion of one of the internal 

 defensive spicula, to exhibit variety in the basal portion. 

 X 250 linear. 



Fig. 6. — One of the equi-anchorate, retentive spicula. 

 X 630 linear. 



Since the completion of this plate I have obtained a 

 very much larger and finer specimen of this species, which 

 is figured in the supplemental Plate LXXIX of this 

 volume. 



MiCKOC'iONA L.EVXS, Bo'werbcmh. 



Vol. ii, p. 127, ' Moil. Brit. Spongiadas.' 



Fig. 7. — The type-specimen of M. tevis from Shet- 

 land. Natural size. 



Fig. 8. — One of the attenuato-acuate, tension spicula 

 of the dermal membrane. X 160 linear. 



The tension spicula of the dermal membrane in the 

 specific description of the sponge in vol. ii, p. 127, 

 has been printed in error as " attenuato-acerate," 

 whereas it should have been attenuato-acuate. 



Fio-. 9. — One of the tricurvo-acerate tension spicula 

 of the dermal membrane. X 250 linear. 



Fio-. 10. — An attenuato-acuate skeleton spiculum. 

 X 80 linear. 



Fio-. 11. — An attenuato-acuate, entirely spined, inter- 

 nal defensive spiculum. X 150 linear. 



