176 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



and posterior spermathecse are of the same size. Septa (according to a sec- 

 tion placed at my disposal by Professor Frank Smith): — 



V/VI, VI/VII, VII/VIII, VIII/IX, IX/X, X/XI, XI/XII, XII/XIII, 

 XIII/XIV. 



Habitat. — Havana, Illinois. Professor Frank Smith 

 kindly furnished me several specimens. 



Detailed Description. 



Genital Zone. — The genital zone is slightly sunken, very 

 much as in Smith's specimens of D. communis, but to a 

 lesser extent. The centre of the zone in XIX is higher, 

 while the depression exists in XVIII and XX. But even 

 the depressions are slightly elevated in the centre, so that 

 there appear to be four separate depressions, one in each 

 corner of the zone. The ridge surrounding the zone is 

 very low. There is one pair of papillse in the posterior part 

 of XVII and one smaller pair in XX. One specimen pos- 

 sesses a large median papilla in XVI/XVII. In this 

 papilla are seen two distinct depressions, giving it the ap- 

 pearance of being double. The papilla is strictly median 

 and not in line with the papilla of the zone, which latter are 

 all in line with setae ab. 



Sperm,athecce. — As these organs have not been figured, 

 and as their shape is of considerable importance, I have 

 thought best to give two figures (143, 144) of the two 

 spermathecse from the same side of a specimen. 



Sperm-ducts. — According to longitudinal sections lent me 

 by Professor Frank Smith, the sperm-ducts generally run 

 between the ccelomic epithelium and the longitudinal mus- 

 cular layer. Here and there, however, they are covered 

 by a single strand of muscles. The same characteristic is 

 also found in D. co^nmunis. According to a private com- 

 munication to me by Professor Smith, the statement by 

 Garman, that the ducts in D. communis run entirely in the 

 muscular layer, is considerably misleading. Even in this 

 species the ducts are merely covered by the coelomic epithe- 

 lium and not by muscular strands as in Trigaster. 



