chap, in.] THE CRUISES OF THE 'PORCUPINE: 95 



and in the afternoon, rapidly passing over the edge 

 of the plateau, we dredged in 725 fathoms with a 

 bottom of muddy sand (Station 36). This is about 

 the bathymetrical horizon at which we find the 

 vitreous Sponges in the northern area ; and although 

 the bottom is here very different, much more sandy 

 with but a slight admixture of globigerina ooze, we 

 dredged a specimen, tolerably perfect though dead, 

 of Aphrocallistes bocagei, Wright, a vitreous sponge 

 lately described by Dr. E. Perceval Wright from a 

 specimen procured by Professor Barboza de Bocage 

 from the Cape- Verde Islands, and one or two small 

 specimens of Holtenia carpenteri, Wy. T. The muddy 

 sand contained a considerable proportion of gravel 

 and dead shells. 



On Thursday, July 22, the weather was still re- 

 markably fine. The sea was moderate, with a slight 

 swell from the north-west. We sounded in lat. 47° 38' 

 N., long. 12° 08' W., in a depth of 2,435 fathoms 

 (Station 37), when the average of the Miller-Casella 

 thermometers gave a minimum temperature of 

 2°5 C. 



As this was about the greatest depth which we had 

 reason to expect in this neighbourhood, we prepared 

 to take a cast of the dredge. This operation, rather 

 a serious one in such deep water, will be described 

 in detail in another chapter. It was perfectly suc- 

 cessful. The dredge-bag which was safely hauled 

 on deck at 1 o'clock on the morning of the 23rd, 

 after an absence of 7^ hours and a journey of up- 

 wards of eight statute miles, contained H cwt. of 

 very characteristic grey chalk-mud. The dredge 

 appeared to have dipped rather deeply into the 



