EXPLANATION OF PLATES. 



All the figures with one exception were drawn from nature 

 by the author. The pen-and-ink reproductions are by Mr. S. 

 F. Denton and the author. The original drawings were free- 

 hand, and were often made under very unfavorable circum- 

 stances, on board ship, in temporary working places, or in the 

 open air. All figures, unless otherwise indicated are very 

 much enlarged. 



The figure of Chiorcea leontina (PL vi, fig. 2) was made by 

 A. Agassiz, copied by Denton. 



Plate i. 



Fig. 1. Velella Meridionalis sp. nov. Probable not an adult, 

 although from a specimen much larger than that shown in figs. 

 2,3. 



Fig. 2. The same seen from the under side. The central 

 body of bright blue color is the "feeding polyp" and the small 

 blue tentacle-like structures about it mark the limit of the 

 "float" (see description) as seen from the lower side. The 

 oval body forming that portion outside the float is the umbrella 

 seen from below. 



The umbrella also forms a conspicuous part of fig. 3, but 

 from the fact that it is seen from the edge is not so conspicu- 

 ous in fig. 1. 



Fig. 3. Velella seen from above. The oval body forming 

 the great mass of the animal is the umbrella as explained above. 

 Tiie smaller oval body placed diagonally on the larger is the 

 float seen from above. In this float the concentric lines indi- 

 cate the edges of the chambers wliich make up the float. The 

 thin plate extending across the float is the triangular sail, 

 shown from the side in fig. 2, and seen in perspective. This 

 sail is much larger in the specimen figured in fig. 1, than in 

 that shown in fig. 3. The upturned edge of the umbrella shown 

 on the right of fig. 1 corresponds with the upper pole of fig. 3. 



(47) 



