397 



Fig. 1. 



Fig. 2. 



from behind. It represents a transverse section through the body epi- 

 thelium {ej}) just posterior to the appendage [the line of section is 

 indicated in Fig. 2 by the line marked (Fig. 1)], and also gives a view 

 of the posterior side 

 {ap) of the latter. This 

 side is well defined, 

 nearly perpendicular 

 to the body -surface, 

 and quite free and ex- 

 posed. The epithelium, 

 ep, which represents 

 the level of the body- 

 surface, is invaginated, 

 in the form of a little 

 pocket, p.s, lying near- 

 er to the lateral than 

 to the medial part of 

 the appendage, and si- 

 tuated at the base of 

 the latter. This is the 



well-known pulmo- 

 nary sack. 



On the posterior 

 surface of the appen- 

 dage towards its medial 

 part two oblique and 

 parallel furrows, fi 

 and f2, appear, nei- 

 ther of which, however, 

 reach quite to the base. 

 They are so situated 



Fig. 1. Outline of posterior side of 1. abdominal 

 appendage drawn from a wax reconstruction , shewing 

 some of the pulmonary furrows (/I— /4) and the body- 

 epithelium {ep) in transverse section just posterior to 

 the appendage. 



Fig. 2. Longitudinal section through same appen- 

 dage, cutting the 1. furrow and the medial end of the 

 2. furrow. 



Letters to both figures: ant , post, lat, med = an- 

 tnat, II prottucea, trie terior, posterior, lateral, and medial sides of the appen- 

 medial and deeper fur- dage. coel 7—9, 7— 9th coelomic sack. En region of 

 the epithelium at base of appendage, which produces 

 the entapophysis. ep body epithelium, epl epithelium 

 of distal wall of 1 furrow. //, /2 two oldest pulmonary 

 furrows. f3 commencement of 3rd furrow. f4 position 

 of the 4th furrow (not yet present in this stage), gen.dt 

 new furrows (two of genital duct, in section, p. s pulmonary sack. 

 which, /3, /4, are 



sketched in the figure) are successively added, parallel to and re- 

 sembling the first two, but all situated within the pulmonary sack, — 

 except, perhaps, the third, f2,, which ist just on the edge of the 



row, fi , would 

 more distal than 

 lateral one, f2. 

 the following; stages 



lie 



the 



In 



