ON THE DEVELOPMENT OF LINGULA ANATINA. 



Ill 



XV. DESCRIPTION OF PLATES. 



All figures are camera drawings with the exception of PI. 

 VI., Figs. 88, a and b. Magnification of each figure is noted in its 

 explanation. Some figures are represented as accurately as possible 

 in natural colors. In other cases it may be understood that the 

 colors employed are of merely diagramatic value ; thus : — 



shell yellow 



muscle red 



nephridi urn green 



and other parts g ra J- 



The following abbreviations are used throughout the plates : 



am. ap arm apparatus. 



am. rg arm ridge. 



am. sn arm sinus. 



ant. dr. fo;.... anterior dorsal lobe of 

 liver. 



arch archenteron. 



ax axial tube of nephridinm. 



bd. cv body cavity. 



cl ccelomic sac. 



cr cirrus. 1 



cr. en cirrial canal. 



dr. mes dorsal mesentery. 



dr. mt dorsal mantle. 



dr. s7i dorsal shell . 



epsl epistome. 



fn funnel of nephridium. 



gl. ell gland cell of mantle. 



gm. ell germ cell. 



gr. am. sn great arm sinus. 



gst. pr. 6c?....gastroparietal band. 

 il. pr. bd. ...ileo-parietal band. 



int intestine. 



int. mes intestinal mesentery. 



lot M. lateralis. 



It. gn lateral ganglion . 



m mouth. 



m. br brachial muscle. 



m. br. Ig. ...longitudinal arm muscle. 

 m. br. tr. ...transverse arm muscle. 



m. cr cirrial muscle. 



m. dr dorsal muscle. 



on. pd peduncular muscle. 



1. The Roman numerals annexed show the order of the formation of the cirrus. 



