No. 3] LOXOSOMA DAVENPORT/. 367 



sexes are separate, and that the males are larger than the 

 females, although he considers the number of his observations 

 insufficient to establish the law. Since, according to my ob- 

 servations on L. Davenporti, the male condition indicates a 

 greater age than the female, we might reasonably expect that 

 the average male individual would exceed the female in size. 

 Nevertheless, I do not find evidence that such is the case. 

 All of the males which I have studied (about ten) were of 

 nearly average size. All of the exceptionally large individuals 

 which I have observed, specimens 2 mm. or more in length, 

 have without exception been females. In view of these facts, 

 Prouho's generalization cannot be accepted as applying to the 

 American species. Neither do I consider that my observations 

 upon so small a number of males justify the opposite conclusion, 

 namely, that the average size of the females exceeds that of the 

 males. So far as size may be considered to have any bearing 

 upon the matter, the facts observed would seem to lend support 

 to my suggestion that several periods of sexual activity, alter- 

 nately male and female, occur in the life of a single individual. 

 The gland cells, which have been described hitherto as occur- 

 ring in the vicinity of the brain, have been those of the shell 

 gland. PI, XXXIII, Fig. 2"/, represents a cell which evidently 

 plays a different role. Although lying closely associated with 

 the cells of the shell gland, it sends out a long process extending 

 to the epithelium of the upper part of the oesophagus. From 

 the coarsely granular character of the cytoplasm and the appear- 

 ance of the process (PI. XXXIII, Fig. 28), I consider it a gland 

 which pours its secretion into the upper part of the oesophagus, 

 probably to aid in the entanglement and deglutition of food 

 particles. This condition has been observed only in the case 

 figured, which is probably to be accounted for by the fact that 

 only in an exceptionally favorable section (longitudinal and ob- 

 lique to the sagittal plane) could both the cell and its process 

 be made out completely. A fact which is of interest in this 

 connection is that in sagittal sections the cilia of the upper 

 part of the oesophagus just beneath the epistome have been 

 noticed in some cases to stain differently with iron-haema- 

 toxylin and orange from those of other regions. While the 



