EXPLANATION OF PLATE XXXIII. 



FIGURE 246. Cynthia partita, variety stellifera, (p. 701;) natural size. 



247. Cynthia caruea, (p. 701 ;) natural size. 



248. The same, (p. 701 ;) younger specimens, natural size. 



249. Eugyra pilnlaris, (p. 700 ;) natural size. 



250. Molgula Manhatteusis, (p. 699;) smooth variety, natural size. 



251. Molgula areuata, (p. 699;) natural size. 



252. Botryllus Gouldii, (p. 702 ;) colony incrusting the stem of Tubularia, 

 somewhat enlarged. 



253. The same ; one of the zooids, enlarged ten diameters ; a, anal tube and ori 

 fice; s, somach ; g, groove and vessels along the edge of the branchial 

 sac, inside ; o, left ovary : &, bud, attached by a slender stolon. 



254. Salpa Cabotti, (p. 706 ;) solitary individual, from the dorsal side, enlarged ; 

 h, heart; s, small chain of salpu3 budding within the old one. 



255. The same ; one of the individuals from a mature chain, three-quarter 

 view enlarged ; a, posterior or anal opening; &, anterior or branchial 

 opening; c, processes by which the individuals of the chain were 

 united ; h, heart ; n, nervous ganglion ; o, nucleus ; r, gill. 



256. Escharella variabilis, (p. 713 ;) few of the cells, much enlarged. 



(Figure 2515 was drawn by A. Hyatt ; 254 and 25,1 were copied from A. Agassiz ; the others were 

 drawn by A. E. Verrill.) 



