ORTMANN : THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 375 



The specimens from the Lake Erie drainage in Conneaut Creek quite often liave 

 two spines (eight specimens out of twenty-two), and thus correspond to the Beaver 

 River form, and to those from Elk ( "reek, in which one specimen out of six lias two 

 spines. Tlius it appeare that tlie form in the drainage of Lake Erie more closely 

 approaches the form found in the Beaver River tlian that found in French ('reek, 

 although it must he granted that tlie material at hand seems to he not entireh' 

 satisfactory, being somewhat too scanty from French ("reek, and decidedly insuf- 

 ficient from Elk Creek. 



A feAV freaks have come under observation in the following cases : 



1. As has been said, the rostrum reveals in old individuals a tendencj' to a 

 shortening of the acumen. The extreme is reached in a specimen (male of the first 

 form) 74 mm. long, from Conneaut Outlet, Ci-awford County (D. C. Hughes coll.), 

 where the acumen is broadly triangular and hardly longer than the short marginal 

 spines, reaching onl}' to the distal end of the basal joint of the peduncle of the 

 antennula. The acumen is well formed (not deformed), showing no traces of injury. 

 But that this specimen undoubtedly has been injured at some time earlier in its life, is 

 revealed by the fact that both claws are comparatively' small, and by the characters 

 of regeneration (lack of spines on the outer lower margin of the meropodite, the 

 absence of a tubercle on the anterior margin of the loAver side of the carpopodite, 

 and the generally weak and slender shape). 



2. A female (46 mm. long) from lirokenstraw Creek, (Jarland. Warivn ("ounty, 

 has the acumen of the rostrum directed obliquely to the left side, and the right 

 margin of the rostrum has five marginal spines. This seems to be due to an injury 

 received in earlier life. The left claw is also smaller and of the regenerated type. 



3. A specimen (5.5 mm. long) from the Alleghany River at Sandy Creek (col- 

 lected by the writer, Nov. 19, 1904, Cat. No. 74. 479), has the characters of a female 

 in the shape of the chehe and the lack of hooks on the pereio|)ods. The annulus 

 ventralis, however, is very indistinct, although its outlines and slight median 

 depression are visible, as is also the median fissure. l>ut this inilividual has the 

 male genital opening in the coxopodite of the fifth pereiopod, and the first pleopod 

 is of the male type, although small ; it is unusually short, reaching only to the 

 anterior margin of the coxopodites of the fourth pereiopods ; it is of the type of the 

 first firm, wilii a distinct shouldci-; tiic outer part is horny and <listinctly longer 

 than the inner part. 'I'lic srcoml ])ieopods are entirely of the male type. Accord- 

 ing to the sexual orifice and the copulatory organs, we are to regaril this as a male 

 with certain female characters. 



4. A pendant to the last specimen is i)ne (G7 mm. long) from the Ohio River, 



