BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 20. AFD. IV. N:0 1. 5 



(4), but it proved afterwards to be only a variety of Gamharus 

 pellucidus witli fewer and smaller spines. Can now the spe- 

 cimens from Florida be identitied with any of the hitlierto 

 known species of blind Cambarus from North America? I 

 think not, and what follows plainly shows why. Cambarus 

 hamuJatus (6) belongs to a gronp of species with the third 

 segment of only third pair of legs hooked; the iirst pair of 

 the abdominal appendages of the male thick, the inner and 

 <jnter parts each terminating in a short recnrved tooth. ' The 

 Florida-form on the other hand belongs to the iirst group 

 (according to Faxon [6]) with the third segment of third and 

 fonrth pairs of the legs of the male hooked; the first pair of 

 the abdominal appendages of the male with the outer part 

 truncated at tlie tip, with one to three recnrved teeth; the 

 inner part terminated by a short acute spine etc. That is in 

 itself enongli to show the difference, but there are other cha- 

 racteristics too, for instance the rostrum is of quite a different 

 shape in the two forms, and of the strong, sharp spines at the 

 base of the antenns and of the spines just behind the cervical 

 groove on each branchial region of C', hamulatus there is no 

 trace in tlie Florida-form. Camharus setosus belongs to the 

 same group as C. hamulatus, and is thus both by the charac- 

 teristics of the group and by its hairy appearance, the strength 

 of the ('helte etc. easily distinguislied from the Florida-form. 

 This is rather more related to Camharus pellucidus and belongs 

 in fact to the same group of species. But they are fully 

 distinguished from each otlier nevertheless, as is plainly seen 

 on comparison. The rostrum of C. pellucidus is longer (even 

 ill forma inermis) and is always sharply pointed, and the 

 lateral teeth are prominent, long in the typical form, shorter 

 in the inermis. The rostrum of the form from Florida is 

 shorter, broader, more excavated and it ends very blunt at 

 the tip; the lateral teeth are less developed and do not form 

 spines as in C. pellucidus. The antennal lamells are broader 

 in the Florida-form, but have smaller, hardly conspicuous 

 spines. In his Orconectes inermis» too Cope (4) describes and 

 draws spines on both sides of the carapax which are still more 

 developed on the typical C. pellucidus at different points of 

 the carapax, but of those there are no traces in the Florida- 



* Faxon: Revision of the Astacidfe. Mem. Mus. Comp. Zool., Harvard 

 Collesje. Cambrida-e Mass. liSsr). 



