80 LIVERPOOL MARINE BIOLOGY COMMITTEE REPORT. 



orange," whilst the other is " blood red ; " and its spicules 

 are rather stout acuates, whilst those of H. sanguinea are of 

 the same form but longer. 



L. M. B. C, No. 85. 5. Collected in shore pools at 

 Kitterland, near Port Erin, Isle of Man. 



L. F. M., No. 32. 3. 73, 1. Collected at Holyhead. V. 



Group ISODICTYOSA. 



Isodictya varians, Bk. 

 This sponge, belonging to the group Isodictyosa, rather 

 resembles Chalina ocidata in appearance — compare plates 

 Ixvi and Ixxxviii in Dr. Bowerbank's third volume — but it 

 differs greatly under the microscope. The skeleton of 

 C. ocidata is a horny fibre cored with spicules, whilst that 

 of I. varians is a structure made up of spicules merely 

 held together, where they touch each other, with horny 

 matter ; the spicules are simply cemented together thus, 

 and are not enclosed in horny fibre. This difference 

 distinguishes the Chalinas from the Isodictyas, and these 

 species, which rese-mble each other so much in form, are good 

 examples of the two groups. The orders Rhaphidonemata 

 and Holorhaphidota run together in Isodictya, and perhaps 

 the group of Isodictyosa might without disadvantage be 

 taken out of the latter order and placed in the same order 

 with Chalinida. Dr. Bowerbank's plate Ixxxviii in his 

 third volume is from a specimen in the Liverpool Free 

 Museum, one of a large number taken at low water near the 

 old ferry slip at Egremont by myself, in company with Mr. 

 T. J. Moore, in 1869. It was found flourishing in the 

 bed of a stream of warm fresh water running from the 

 engine-house connected with the slip. The fact that this 

 marine species was found in brackish water growing luxuri- 

 antly within the influence of a fresh water stream, becomes 

 of great interest when considered in relation to a fresh- 



