Vol. XLVIII. April, 1925. No. 4. 



BIOLOGICAL BULLETIN 



STUDIES ON THE SECONDARY SKXIAL CHARAC 

 TERS OF CRAYFISHES: II. FEMA1 ESOFCAMBARl - 

 PIR/L/S WITH MALE SECONT)AK\ M X! \l CHAR- 

 ACT! RS 



C. L. TURNER. 

 ZOOLOGICAL LABORATORY. BKI 



I >urin^ tin- spring and summer of i<uj IH! ii.\; tin- writer 



di-< o\ rn-d nineteen specimens of Canihurns f>rof>ini]ims that 



I'd to some decree secondary sexual character- >l both 



68. A close examination revealed that all \\rrr him tional 

 trin. ilrs, some of them bearing eggs when taken but possessing in 

 addit ion tot he usual female secondary i-exual character- tn mi < >nr 

 ! ihrrr male secondary sexual characi- \vell. A mimlier of 



male- \\ere tound bearing extra male ch.ira-ter> and t\\o female^ 

 uiili extra female characters. These re>ult> l.-(| to the exami- 

 nation o| a f.iirly large collection of Canilxiri's -drills \\hicli had 

 alrra<l\ lieen made and also to the search for aberrant condition-, 

 \\hene\er -peciinens came to hand. 



Next to (\iniharns propinqims Canilxims -drills i> tlie mo~i 

 alumd.iiit cra\ !i>h in southern Wisconsin and the t\\o are iiMially 

 taken to^etlu-r in the lakes and stream-. 



l\ IHRSEXES IN Canihurns ririlis. 



Specimens from Delnrun Lake. 



Inti-i>e\e- in ( 'ambarus virilis were tir>t found in 1 )e!a\an Lake 

 "ii June ID. [923. Subsequent collecting trip> \\ere made on 

 June I I. June 14. June 30 and November 20. On June 10 lifty- 

 seven mature females were taken, of which thirty-fight were 

 earn inc e^-. Thirty-seven of those carrying eggs had in addi- 

 tion to a full complement of female secondary -extial characters 



225 

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