Aimtomy of Avs/r(i/!<i h. Aiit/iliibia. 223 



Cv.STIdNATIIID.'E. 



Criiiia sij^^iiifcra. Chiroleples alboouttadis. 



lleleiopoiiis piciits LiiiiiiodMiasles dorsolis. 



In the consideration of the two points especially dealt with 

 in this paper, a study of the general structure of the kidney 

 and testis also l)ecoines necessa,r\\ 



A. — TlIK OpkNINGS of TIIK NkHJIUOSTOMKS FItO.M THE COELOM. 



The si)ecial interest of the Nophrostouies, or openintrs from 

 the body cavity, in connection with the kidneys, ais has pre- 

 viously been pointed out, lies in (1) the fact that they exhibit 

 according to the findings of Marshall, Bles, Frankl and Far- 

 rington (vide infra) in the forms examined by them, a good 

 example of transference of the structural relationships aind func- 

 tion of an eml)ryonie organ during development, amd {'1) the 

 inqjoi'tance of determining the exact forms in which an organ 

 present in the embryo loses its function or ceases to exist in 

 the adult. That these nephrostomes are present in the larval 

 Amphibian, as well as in the embryo of other groups, i-s well 

 known : that they persist in the adult of many of the Fishes 

 and of the Urodeles or " tailed-Amphibiai," still with their em- 

 bryonic relationship to the uriniferous tubules of the kidney is 

 also an accepted fact, their function in this ca>e being doubtless 

 the passage of fluid material from the coelom to the exterior. 

 Moreover it is just as certain that they do not normally persist 

 in the adult of the higher Vertebratai. It becomes desirable 

 then to ascertain just where these structures disappear as a 

 feature of the adult, and what changes take place in their r^ 

 lationships and function during their disappcaa-ance. 



Historical. 



The history of the discussion as to the presence and relation- 

 ships of the nephrostomes in the Anura is a very interesting 

 one. I give it here in brief outline: — 



1874-. Heidenhain. [Ecker, pp. 327, 336] was unable to find 



them. 

 1875. Spengel. [Spengel. "77, and Marshall and Bles, '90. p. 

 147] stated that the nephrostomes open on the 



