Ill 



PLATE XLV. 



IIalichondeia Digkiei, Binverhanlc. 



Vol. ii, p. 253, ■ Mon. Brit. Spongiadaj.' 



¥\g. 1. — Represents the type-specimen received from 

 Dr. Dickie. Natural size. 



Fig. 2. — A mucronato-cylindrical spiculum, from the 

 dermal membrane. X 250 linear. 



Fig. 3. — One of the subclavate, hastate spiciila, 

 from the dermal membrane. X 250 linear. 



Fig. 4. — An acuate, entirely- spined spiculum, from 

 the skeleton. X 260 linear. 



Fig. 5. — One of the large, bidentate, equi-anchorate, 

 retentive spicula. x 530 linear. 



Fig. 6. — A large, tridentate, equi-anchorate spiculum, 

 from the inner surface of the dermal membrane. 

 X 530 linear. 



Halichondeia geanulata, Boiverhcmh. 



Vol. ii, p. 262, ' Mon. Brit, Spongiada).' 



Fig. 7. — Represents the type- specimen received from 

 the late Mr. Joshua Alder. Natural size. 



Fig. 8. — One of the submucronate cylindrical spicula, 

 from the dermal membrane, x 250 linear. 



Fig. 9. — A large, bidentate, equi-anchorate, retentive 

 spiculum, from the dermal membrane. X 530 linear. 



Fig. 10. — A small, tridentate, equi-anchorate, re- 

 tentive spiculum, from the dermal membrane. X 530 

 linear. 



Fig. 11. — One of the acuate, entirely and incipiently- 

 spined skeleton spicula. X 250 linear. 



Figs. 12 and 13. — Two of the attenuate -acuate, 

 entirely-spined, internal, defensive spicula. X 250 

 inear. These spicula differ greatly in size. The two 



