BRITISH SPONGIAD.E. 145 



them, and they were ^th of an inch and -^th of an inch in 

 length. The whole of them are distinctly clavate at the 

 base. The spines are short, conical, acutely terminated, 

 and very numerous. 



The tension spicula of the interstitial tissues are exceed- 

 ingly slender; the greater portion of them are collected 

 into fasciculi, each containing a considerable number of 

 spicula, the bases and apices in each bundle being always 

 coincident. The fasciculi occur singly, and are irregularly 

 dispersed on the surface of the basal membrane. A solitary 

 spiculum may be observed occasionally, but this appears to 

 be rather the exception than the rule. In a young specimen 

 of this species sent to me by the Rev. Walter Gregor, late 

 of Macduff, from the Moray Frith, the skeleton spicula 

 were nearly all clavate or sub-spinulate, but this variation 

 in their form was evidently due to incomplete development, 

 the rest of the spicula also exhibiting evidence of immaturity. 

 The colour, when alive, was light yellow. The specimen 

 was dredged from forty-two fathoms, six miles off shore. 



3. Hymeraphia verticellata, Bowerbank. 



Sponge. Sessile, coating ; surface uneven, with numerous 

 conical projections. Oscula simple, dispersed. Pores 

 inconspicuous. Dermal membrane pellucid, abundantly 

 spiculous ; spicula fusiformi-cylindrical, verticellately 

 spined, very variable in size, dispersed. Skeleton : 

 spicula attenuato-clavate, large and long, distal termi- 

 nations obtuse, few in number; surrounded by nu- 

 merous long and slender inflato-acerate spicula, with 

 incisurate terminations. Interstitial membranes. Ten- 

 sion spicula very numerous, the same as those of the 

 dermal membrane. Basal membrane abundantly 

 spiculous ; same as those of the dermal membrane ; 

 and long, slender, inflato-acerate spicula, with incisu- 

 rate terminations, dispersed or loosely fasciculated 

 Ovaria membranous, aspiculous. 



10 



