BY E. J. GODDARD. 325 



In describing the position of the genital apertures in Glossi- 

 phonia hete?'oclita, Blanchard says, " Porus genitalis masculus 

 inter annulos 25-26, vulva inter annulos 27-28 hians." 



Castle, in his carefully written account of the Fresh Water 

 Rhynchobdellidae of North America, says " Blanchard is certainly 

 in error in his description of the position of the genital apertures," 

 and points out that there is a single united aperture situated 

 between the twenty-eighth and twenty-ninth annuli. 



Body-wall and body-substance.-— Much has been written on this 

 subject. Bourne has given an excellent description in a com- 

 parative way of the important genera of the Hirudinea. I do 

 not hope to add any great amount of information to Bourne's 

 account, but intend to furnish some notes of specific character 

 which may be of some use in connection with that already 

 published. 



The body- wall consists of five layers — cuticle, epidermis, 

 dermis, circular muscle fibres, longitudinal muscle fibres. 



The cuticle calls for no special remark beyond that it is pro- 

 duced into a great number of microscopic papillae into which rise 

 corresponding projections of the epidermis and dermis. No nerve 

 connections could be made out, but they possibly may have some 

 tactile or sensory function, or again may be due to the state of 

 contraction of the organism. 



The epidermis consists of a single layer of columnar cells with 

 a fairly large nucleus. Some of the ceils are enormously enlarged 

 to form large pear-shaped glands which are sunken to a great 

 depth from the main epidermal layer so as to lie on the external 

 surface of the circular muscle mass which lies beneath the dermis 

 and imbedded in the dermis. The glands contain a finely 

 granular substance which, like the glandular cells themselves, 

 takes an intense stain with hematoxylin. The glands 

 are much more abundant in connection with the dorsal 

 than with the ventral surfaces. In the dorsal and the latero- 

 ventral regions one makes out clearly two distinct tiers of epi- 

 dermal glands, one tier being deeply seated, the other more 

 superficially situated and consisting of much smaller elements 



