84 



MARINE ANIMALS OF MASSACHUSETTS BAY. 



to judge of their beauty one should see them in the Gulf of Mex- 

 ico, sailing along with their brilliant float fully expanded, their 

 crest raised, and their long tentacles trailing after them. 



Fig. 118. 



Fig. 119. 





p 



^i4s/ 



, ;v,-i :jm\Y-x . ''&*-- / 



HP 



^|'MM 



^1rPl\b 



\C I. 



Velella. (Vddla mutica Bosc.) 



Another very beautiful floating Hydroid, occasionally caught 

 in our waters, though its home is also far to the south, is the 



Fiir. 120. 



Fig. 121. 



m 



H >v 



W8tffi&fc '\ 



^~~^ '- "< ''\'^" ~ ' ' ">' '*' h - " ' ' | 



Yelella (Fig. 120). It is bright blue in color, and in form not 

 unlike a little flat boat with an upright sail. Its Medusa 

 (Fig. 121) resembles so much that of some of our Tu'm- 

 larians, that it has actually been removed on this account from 

 the old group of Siphonophorae, and placed next the Tubula- 

 rians ; another evidence of the close affinity between the former 

 and the Hydroids. 



Fig. 118. Bunch of Hydrse ; a base of attachment, bb b single Hydrae, c c tentacles. (Agassiz.} 



Fig. 119. Bunch of Hydrae ; cluster of Medusae ; b b Hydrae with tentacles, c d bunches of Medusae. 

 ( Jyassiz.) 



Fig. 120. Velella; m so-called mouth, a tentacles. (Ayassiz.) 



Fig. 121. Free Medusae of Velella ; a proboscis, b chymiferous tube, c circular tube, 



