PLATE XLVIII. 123 



appears to be very widely distributed, and to be by no 

 means so rare as it was at first imagined to be. 



IsoDiCTYA Peachii, Bowerhmilc. 



Vol. ii, p. 276, ' Mon. Brit. Spongiacte.' 



Fig. G. — Represents a specimen of the species from 

 Gruernsey in a fine state of preservation. In the 

 cabinet of the Rev. A. M. Norman Natural size. 



Fig. 7. — One of the skeleton spicnla. x 250 

 linear. 



Fig. 8. — -One of the tension spicula, from the inter- 

 stitial membranes. X 250 linear. 



IsoDiGTi'A PERMOLLis, Bowevhank. 



Vol. ii, p. 278, ' Mon. Brit. SpongiadEe.' 



Fig. 9. — Represents a specimen of the species from 

 Scarborough sent to me by Mr. Bean. Natural size. 



Fig. 10. — A skeleton spicnlum. X 250 linear. 



The Rev. A. M. Norman obtained a specimen of this 

 species from Strangford Lough, October 5th, 1869. It 

 was of a light brown colour. The anatomical structure 

 was identical with that of the type-specimen, and the 

 dermal membrane was in a fine state of preservation, 

 A small piece mounted in water exhibited the pores in 

 an open condition, from one to three occupying the 

 areas of the network produced by the terminations of 

 the distal ends of the skeleton tissue immediately 

 beneath the dermal membrane. 



IsoDiGTYA siMULO, Boiverbanh. 



Vol. ii, p. 279, ' Mon. Brit. Spongiadte.' 



Fig. 11. — Represents the type-specimen of tJie 

 species in the cabinet of the Rev. A. M. Norman. 

 Natural size. 



