Ill 



KKPOKTS FROM THE IXDIAXA UXIVEIiSITY BIO- 

 LOGICAL STATION AT AVINOXA LAKE.* 



II. The Individuality of the Maternal and Paternal Chromo- 

 somes IN THE Hybrid Between Fundulus IIetero- 



CLITUS AND MeNIDIA XoTATA. 

 "W. J. MOEXKHAUS. 



[Abstract.] 

 In the hylirid liotwocn FiiiKluliifi Jictcroditiis and Miiiidia iiofata it is 

 possible to distinguish the chroniosoiues that come from each parent. 

 The chroniosomcs of Fiiiiihihis hctcniclittis are long and straight Avhile 

 those of MniUlUi iiotntn are short and slightly curved. This difference 

 they maintain in the hybrids. They can best be distinguished during the 

 anaphases. They can not be distinguished in the resting stage. During 

 the first two cleavages each kind of chromosome remains grouped bilat- 

 terally upon the spindle. After the second cleavage they become mingled 

 upon the spindle, but the two kinds still retain their individuality and 

 can readily be identified Tliey have been thus traced to a late cleavage 

 stage, as far as was attempted. 



b. An Extra Fair of AppENDAtiEs Modified for Copulatory 

 FuRPOSEs IN Cambarus Viridis. 



W. J. MOEXKHAUS. 



Among the crayfishes used for dissection iu the laboratory we came 

 upon a specimen that had three pairs of abdominal appendages modi- 

 fied for copulatory purposes. This is the first time I have ever seen such 

 abnormality and, furthermore, have not been able to find mention in 

 literature of a similar occurrence. I have, therefore, thought it worth 

 while to make a uole of it. 



The specimen belonged to the species viridis and was about three 

 inches in length. Unfortunately the specimen had been so mtich mu- 



' Contribution? from the /.oiiiogical Laboratory of Iiuliana I niversity under the direc- 

 tion of r. H. Eigenmann. No. 53. 



