76 LIVERPOOL MARINE BIOLOGY COMMITTEE REPORT. 



Order ITL— PSAMMONEMATA. 

 Family. — Arenida. 

 Dysideafragilis, Johnston. 



This sponge, which is found all round our coasts, and is 

 widely distributed over other parts of the world, was called 

 fragilis by Dr. Johnston* because when dried it is easily 

 made to crumble away. This arises from the nature of its 

 skeletal parts. The skeleton is composed of grains of sand 

 taken up by the sponge from the wash of the tide, and 

 worked into a network by being agglutinated together by a 

 very small quantity of horny material. Consequently when 

 the sponge is dried, the horny matter being in such small 

 proportion, the grains of sand easily become separated and 

 the skeleton breaks up. It is the Spongelia of Dr» 0. 

 Schmidt. + Only two British representatives of arenaceous 

 sponges have been described. Mr. Carter has placed them in 

 his order Psammonemata, which also contains the " Sponge of 

 Commerce " or " bath sponge," whose skeleton is clear horny 

 material, almost entirely, if not altogether, free from grains 

 of sand. Mr. Carter, however, states that there are always 

 some grains of sand to be found in some parts of the fibre of 

 even the best specimens of " Turkey Sponge." The order, 

 therefore, contains every variety of arenaceous fibre, from 

 Si)ongia officinalis to such sponges as Dysideafragilis, 



L. F. M., No. 24. 5. 73. 14. Collected at Holyhead. 



Order IV.— RHAPHIDONEMATA. 

 Family. — Ch alinida. 



Chalina oculatay Bk. 



Halicliondria oculata, J. 

 Chalina pohjcliotoma, Carter. 

 Spongia polychotoma, Esper. 



* British Sponges, p. 187; see also Bowerbank, Mon. Brit. Spong., 

 vol. i, pi. xiv., fig. 270 ; vol. ii, p. 381, and vol. iii, pi. Ixix. 

 ^ Spong ienfauna Allan., 1870, p. 77. 



