328 MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 



LETTERING OF THE PLATES. 



Jb I, Ab II, Ah III, first, second, and thir<l pairs of abdominal appendajjes of the eiiiUryo. PI. xvii. 



«»., anus (=proctod£eum). PI. xvii. 



ant. St., auterior branch of the stalk of the mushroom body. 



lat app.gang., ganglion of the first pair of appendages. 



opp.' n., nerve of Ist pair of appendages (" cheliceral nerve "). 



asc. St. m. b., ascending branch of the stalk of the mushroom ))ody. 



b. c. J., bulb of the cerebral lobe (" tubercle protocerebrale" of Viall.anes. 

 br., brain. 



c. <j. c, c, g. c'., c. g. c" ., groups of cerebral-ganglion cells. 



ch. c, chromatic cells, small ganglion cells, or aprotoplasmic cells of the mushroom body. 

 c. I., cer. I., eer. lobe, and vh: gang., cerebral lobe or ganglion. 



e. ch., "Chiasma," or bundle of twisted nerve-fibers connecting the outer or third with the second division of 

 the lateral-eye lobes (" Chiasma externe" of Viallanes). 

 c. com., c. 1. com., and com. e. I., cerebral commissure. 

 /., sense organ of embryo. PI. xvil. 



/'. ./'"., bundles of fibers arising from large ganglion cells. PI. vi. 

 fasc, fascia or bundle of fibers arising from the ganglion cells. 

 g. 1st app., ganglion of the first pair of appendages, 

 i. g. I., inner ganglionic layer of lateral eye lobes. 

 /., labrum of embryo. PI. xvii. 



lat. h.. "lateral heap," or " dorsal organ " of the embryo. PI. xvii. 

 lat. eye I., lateral-eye lobe. 



lat. eye I'., proximal or first division of the lateral-eye lobes. 

 lat. eye I-., second or middle division of the lateral-eye lobes. 

 lat. eye P., third or external division of the lateral-eye lobes. 

 lat. eye n., lateral-eye nerves. 

 lat. eye n. r., origin or root of lateral-eye nerve. 

 ;. g. c., large ganglion cells. 



I. St., lateral branch of stalk of mushroom body. 

 I. t. n., I. teg. «., lower tegumental nerve of the brain. 

 m., mouth of the embryo (stomodapum). 

 m. b., mushroom body or pedunculated body, 

 m. eye I., median-eye lobe. 

 m. eye n., median-eye nerve. 



m. eye n. e., external lobule of the median eye-lobes, 

 m. eye n. r., root of median-eye nerve. 



m. It., unpaired fronto-median nerve situated between the lower tegumental nerves, 

 as., oesophagus. . 



n'. to n". neuromeres, or ganglia of the embryo. 

 (B. com., cesophageal commissure or counective. 

 post. ce. com., postojsophageal commissure. Plate xvi. 

 p»-. (T. oo»n., pretesophageal commissure. Plate xvi: 

 St., stomach. Pis. xviii and xix. 

 St. mb., .stalk of the mushroom body. 



s. m. g. c, 8. m. g. c'., small g.angliou cells forming tlic rulHe-like masses of the mushroom body. 

 teg. n., tegumental nerves of the oesophageal ring. 

 M. teg. n., upper tegumentary nerve. 



I, II, III, IV, V, VI, the six pairs of cephalothoracic .appendages. 

 / g., VI g., ganglia of the first and sixth pair of appendages. 



