BRITISH SPONGIAD.E. 259 



fusiformi-cylindrical spicula forming a coarse irregular net- 

 work, and occasionally these spicula exhibit a slight ten- 

 dency to clavate terminations ; the malformed bihamate 

 spicula are few in number, and the angulated inequi-an- 

 ch orate ones are very rare. The sarcode is abundant, and 

 abounds with minute vesicles or cytoblasts and molecules 

 of various sizes. It appears to entirely fill the interstitial 

 spaces, and the interstitial membranes are also thickly 

 covered by it. 



The attenuato-acuate spicula of the skeleton are singular 

 from the unusual irregularity of their form, near the basal 

 termination, arising from the numerous and strongly pro- 

 duced spines with which they are thickly covered, so that 

 in many cases that portion of the shaft has an irregular 

 and distorted appearance. A few attenuato-acerate spicula 

 are found intermixed with the attenuato-acuate ones, and 

 these acerate spicula are medially but not terminally 

 spined. 



This sponge was brought up by the trawl about a mile 

 off shore opposite to the Castle Hill. I have named it after 

 mv late friend Mr. Thomas Insall to whom I am indebted 

 for many interesting specimens of sponges from the British 

 Channel, and for much kind assistance during the course of 

 my studies of the British species. 



Since writing the above, I have found a second specimen 

 on the shore. It agrees in its external characters and size 

 with the first one, but is less latticed in its form ; when 

 preserved in strong salt and water it becomes of a dark 

 purple colour. 



1 subsequently received this sponge in a young state, 

 in the form of a very thin dark stratum on the surface of 

 a fragment of a large bivalve shell dredged by the Rev. 

 Walter Gregor of Macduff, in the Moray Frith. 



21. Halichoncria scandens, Bowerbank. 



Sponge. Coating, parasitical. Surface smooth. Oscula 

 simple, dispersed. Pores inconspicuous. Dermal 



