IX 



X 



?XI 



The pronephros of Chrysemys marginata. 33 



4,17 — 4,23 A tubule with neplirostome at 4,18, aud communi- 

 cation with duct at 4,23. 



4,28 — 4,37 Tubule opening into open nephrotome at 4,29, 

 4,32 and 4,35 (?) and into duct at 4,37. 



4,38 — 4,42 Rudiments of pronephric (?) tubule with more than 

 one opening into nephrotome. 



Mesonephric tubules developing at 4,42 ?, 4,45. 



Pronephros on right side. 

 VI { Glomus begins 3,27. 

 VII { 3,40—3,45 Nephrostome extending from 3,41—3,44. 



I 3,50 — 4,2 Nephrostome 3,50 and 3,51 — tubule opens 

 ^I^I \ into duct at 4,2. 



j 4,8 —4,13 Tubule with nephrostome at 4.8 and 4,9: 

 VIII or? IX ^ Qpgj^g jj^^Q ^^^^^ ^^ 4J2. 



( 4,23 — 4,28 Tubule with nephrostome opening at base of 

 IX I open nephrotome, and connected with duct 



I at 4,28. 



j 4.33 — Tubule opens into nephrotome and duct. 

 \ Difficult to decide how many branches. 



Mesonephric tubules at 4,43 etc. 



Embryo L. 



5 mm. long (not making allowance for cranial flexure). 



Stained with Boraxcarmine (Grenachee's). Counted 23 meso- 

 dermic somites after clearing in xylol. Used 9 slides in mounting, 

 having respectively 52, 52, 39, 39, 39, 39, 39, 39 and 24 sections. 



Body begins 1,4. 

 Left side of embryo Right side of embiyo 



3,22-3,34 VI 3,20—3,32 



3,34—4,7 VII 3,32 -4,3 



Zool. Jahrb. XXXVI. Abt. f. Anat. 3 



