582 



ALEXANDER MEEK 



ventral line is carried to the left, then to the right, and again 

 to the left. At the posterior end of the body, which is 

 laterally flattened, the ventral angle is not that of the ventral 

 nerve but to the right of that hne (Text-fig. 4). 



A still more noteworthy feature of the exterior is the 

 presence of folds of the body-wall, the glandular folds of 

 Spengel. In front they are irregular but mainly transverse 

 (Text-fig. 2) ; behind the gill region they become markedly 



Text-figs. 4 and 5. 



Fig. 4. — Internal surface of alimentary canal at the posterior cut 

 end of the specimen — the region of the liver caeca — to show 

 the disposition of the folds and the real median line to one side 

 of the actual median line. The upper end is anterior. 



Fig. 5. — External view of the body-Mall at the posterior end of the 

 genital region to shoAv the condition of the folds on either side 

 of the ventral nerve-cord. 



transverse on that part of the body-wall below the genital 

 wings, the area occupied increasing as that of the genital 

 wings diminishes. In this posterior portion of the specimen 

 (Text -fig. 5) they emerge from the mid-ventral line as narrow 

 folds which expand into a club shape and narrow again, 

 either ending abruptly or passing into oblique folds of the 

 body-wall. If they end they do so in a series which defines 

 a longitudinal groove, and similar but usually oblique grooves 



