Fi-. 2. 



120 Prof. W. Thomson 07i the Depths of the Sea. 



large ; and, so far from being extinct, my belief is that the 

 group has attained probably a much higher development in 

 our times — that while the pear-encrinites have been losing 

 ground, the Ventriculites have been gaining it. One haul of 

 our dredge in the soft, warm, oozy chalk-mud off the north of 

 Scotland brought 

 up from a depth of 

 500 fathoms up- 

 wards of forty spe- 

 cimens of vitreous 

 sponges. Many of 

 these were new to 

 science, and some 

 of them resembled 

 closely the beautiful 

 Venus's Flower- 

 basket of the Phi- 

 lippines, while 

 among them were 

 probably two spe- 

 cies of Hyalonema, 

 the strange glass- 

 rope sponge of Ja- 

 pan. Four speci- 

 mens of this won- 

 derful new form of 

 vitreous sponge, 

 which I exhibit (see 

 woodcut, fig.2), were 

 brought up in this 

 haul. They were 

 loaded with their 

 glairy sarcode, and 

 had evidently been 

 buried in the ooze 

 nearly to the lip. 

 When one looks at 

 the exquisite sym- 

 metry of these or- 

 ganisms, one almost 

 wonders at the reck- 



Holtenia Carpenteri (Wy. T.). 

 (Half the natural size.) 



lessness of beauty which produces such structures to live and 

 die, for ever invisible, in the mud and darkness of the abysses 

 of the sea. ^ I dedicate with great pleasure, the new genus 

 to which this sponge must be referred to our kind and hospi- 

 table friend, His Excellency M. Holten, the Governor of the 



