CHAr. II.] MADEIRA TO THE COAST OF BRAZIL. 79 



chial sj'stem — associating it, an annelid, or perhaps more strict- 

 ly an aberrant and liigldy specialized nemertid, with ascidians 

 and with Amjjhioxus — brought it into the fraternity among 

 which the first hazy indications of a passage between the inver- 

 tebrates and vertebrates seemed inclined to dawn. The singu- 

 lar history of its development added to the interest which had 

 already been excited by the peculiarities of its structure. In 

 his series of papers on the development and metamorphoses of 

 the larvfie and young of Echinoderms, Johannes Miiller figured 

 and described what he regarded as an echinoderm larva under 

 the name of Tornaria. A couple of years ago Metschnikoff 

 found reason to believe that Tornaria was the larva, not of an 

 echinoderm, but of Balanoglossus ; and within the last year Al- 

 exander Agassiz has confirmed Metschnikoff's view by tracing 

 all the stages of its development from Tornaria to the fully 

 formed worm. 



From the time we entered the current, immediately after leav- 

 ing the Cape Verde Islands, the sea had been every night a per- 

 fect blaze of phosphorescence. The weather was very fine, with 

 a light breeze from the south-westward. There was no moon, 

 and although the night was perfectly clear and the stars shone 

 brightly, the lustre of the heavens was fairly eclipsed by that 

 of the sea. The unbroken part of the surface appeared pitch- 

 black, but wherever there was the least ripple the whole line 

 broke into a brilliant crest of clear white light. Near the ship 

 the black interspaces predominated, but as the distance increased 

 the glittering ridges looked closer, until toward the horizon, as 

 far as the eye could reach, they seemed to run together and to 

 melt into one continuous sea of light. The wake of the ship 

 was an avenue of intense brightness. It was easy to read the 

 smallest print sitting at the after -port in my cabin; and the 

 bows shed on either side rapidly widening wedges of radiance, 

 so vivid as to throw the sails and rigging into distinct lights and 

 shadows. Tlie first night or two after leaving San lago the 



