SECONDARY SEXUAL CHARACTERS OF CRAYFISHES. 269 



ramus a little thicker. There is no trace of the triangular shoul- 

 (U-r which occurs regularly on this appendage in the normal male. 

 This specimen has been dissected and as in the previous cases 

 there have been found well developed ova. This case is unque-t- 

 ionably one of a female with the partial development of male 

 secondary -exual character-. The mak- char.icu-rs are not so 

 -tnmgly developed a- in the previous cases, tlu- ho. .k- . >n the third 

 w. ilking kg- being ab-ent and the second abdominal appendages 

 being modified hut link- from the usual female type. 



Specimen mimher .V i- 47 mm. long. It is without doubt a 

 Ifiii. ik, h.i\ ing ,i iionn.il .mmilu- ventralis and oviducal opening- 

 at t IK- h. i M-< if the third walking legs. The fir- 1 abdominal appcnd- 

 |n-tuliar, however, being unlike on tlu- two -ide-. 

 Tlu- right OIK- i- a normal <limiiuitive female appendage. The 

 k-ft on. Fig. II pp have grown as a bifurcated female 



appendage hilt there I . .\VI1 OUt of it .M I hi- junction of the 



h.i-al and di-tal parts an a| ipendage somewhat -imilar to ami a 

 little -mailer than the normal tirst abdominal appendage >l tin- 

 nd form male. The [ndximal half of the appendage i- ijuite 

 >lender. The MM. .n<l abdominal appendage-, hoih in >i/e and 

 ral loini i. M nihle the normal female a|i|u-iida^i - bin a dis- 

 tinct triangular -houlder like that found in the male i- piv-ent 

 upon the endo|)od: 14 . 



Xf>fi inicH unmln-r (j \\.,~ hearing well-de\'i-lo|>ed eggs u|ioii tlie 

 abdomen \\lien taken SO there was no question a- to the -.-\. It 

 is (>~ mm. in length. The nviducal Opening^ and the aimulus 

 \enirali- are tho-i- of a normal female but the following male 



M rue in re- are also prcM-ni : copulatory hooks on the third walking 



; !u>t .ihdominal ,ippen<l.igi-- much like tin -e of the imrmal 

 tir-t form male: d abdoiiiin.il append. I*;. - like tho-^' of the 



mak- in form but a little -mailer and with the triangular >hoiilder 

 on the eildopodhe Mot SO \\ell de\i-loped . . 



Specimen numher i<>, 55 mm. long, i- umi-ual in that it po- 

 an extra o\ iducal |>ore at the ha-e of the left fourth walking leg in 

 addition to a rather complete complement of both male and 

 female -ccondary >e\lial character- FigS. J, 9 and 141. The 

 annulu- \etitrali- and o\ iducal pore- at the base of the third 

 walking legs are norm.il female character-. An extra oviducal 

 opening is present on the left fourth walking leg but it is 



