OBSERVATIONS ON POLYZOA. 



227 



sixty. The statoblasts vary between .199 m. m. in 

 breadth by .333 m. m. in length ; .233 m. m. in breadth 

 by .349 m. m. in length. The proportions are in equal 

 parts from 6 by 10 to 6 by 12, 6 by 11, and 7 by 10 ; 

 annulus varies from f at the sides to f at the sides and f 

 at the ends. 



PECTINATELLA. 



Coenoecium without cells, the branches being .large 

 lobes with the polypides on the upper side ; naked above, 

 with the ectocyst gathered below into a thick common 

 base for the colonies. Invaginated fold almost obsolete. 

 Statoblasts with spinous annuli, extremities rounded. 



PECTIN ATELLA MAGNIFICA. 



The polypides are arranged on the lobes ; sometimes 

 in single, but generally in double rows, placed alternately. 



The ectocyst is of 

 great thickness at the 

 centre, and may be 

 from four to eight 

 inches in depth ; arms 

 about as long as the 

 evaginable tube of the 

 polypide. 



Tentacles number 

 from sixty to eighty- 

 four. Lower part of 

 these and the mouth 

 parts are crimson. 



StatoblHsts vary 

 from .8 m. m. in 

 breadth to .9 m. m. in 

 length. The propor- 

 tions in equal num- 

 bers are as follows : 

 24 by 27, or 26 by 

 27, 27 by 28, 28 by 

 29, 29 by 30, 30 by 

 30. 



24x27 



FIG. 20, from Mystic Pond, near Cambridge, 

 Mass. Although usually the annulus on the lower 

 side presents a broader surface, as in PI. 10, Figs. 

 3 and 4; this is often so narrow that when meas- 

 ured from above there is no appreciable differ- 

 ence. [The lateral view of the statoblast in PI. 

 10 is correct, and therefore not given here.] 



