EXPLANATION OF PLATE XXXIII. 



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



247. — Cynthia carnea, (p. 701 ;) natural size. 



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



249. — Eugyra pilularis, (p. 700 ;) natural size. 



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



251. — Molgula arenata, (p. 699 ;) natural size. 



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

 somewhat enlarged. 



253. — The same ; one of the zcoids, enlarged ten diameters ; a, anal tuhe and 

 orifice; s, stomach; g, groove and vessels along the edge of the branch- 

 ial sac, inside ; o, left ovary ; i, hud, attached by a slender stolon. 



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

 7(, heart ; s, small chain of salpre 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 ; ft, anterior or branchial 

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

 united; 7i, heart; n, nervous ganglion ; o, nucleus ; J', gill. 



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



(Figure 256 was drawn by A. Hyatt; 254 and 255 were copied from A. Agasaz ; the others were 

 drawn by A. E. Verrill.) 



