340 REPORT OF NEW JERSEY STATE MUSEUM. 



Bartonius Ortmann, 1. c, pp. 97, 117. Type Astacus bart-onii Fabricius, sixth 

 species, designated. (An exact synonym of Cambarus Erichson.) 



Procambarus Ortmann, Ann. Carnegie Mus., Ill, 1905, p. 437. Type Cambarus 

 digueti Bouvier, first species, designated. 



Paracambarns Ortmann, Proc. Wash. Acad. Sci., VIII, 1906, p. i. Type 

 Cambarus (Paracambarus) paradoxus Ortmann, monotypic. 



Ortmannicus subgen. nov. Type Astacus blandingii Harlan. 



Cephalothorax sub-cylindrical. Last thoracic segment with- 

 out gills and free from rest. No traces of rudimentary pleuro- 

 branchise on anterior segments. Hindmost podobranchia with- 

 out any lamina. Branchise total thirty- four, counting those on 

 both sides of thorax. Third or third and fourth (in our species) 

 pairs of legs in male with prominent tubercle or hooks on front 

 border of third segment. First pair of abdominal appendages 

 in males ends in styles, hooks or teeth. More or less mobile 

 annulus placed on sternum in female, just behind penultimate 

 thoracic somite. Females with first pair of abdominal appen- 

 dages, though much smaller than following pairs, simple, and 

 somewhat larger than in Astacus. Telson clearly divided by 

 transverse suture. 



The crawfishes, or crayfishes, are widely distributed over 

 North America, ranging from Lake Winnipeg to Guatemala, 

 and from New Brunswick to Wyoming. 



Commercially the crawfishes are little valued, except as bait 

 to the angler. Though never reaching the size of the Euro- 

 pean species in demand as food, they are not inferior in quality. 

 Their use as bait is chiefly in the angling of the black bass 

 (Micropterus) . Economically they are of value as scavengers, 

 feeding on almost any decayed animal or vegetable substances 

 they may find. In turn many animals prey upon them. Ac- 

 cording to Ortmann, their chief enemies are raccoons, king- 

 fishers and other aquatic birds, water snakes (Matrix sipedon and 

 Regina leheris), mud puppies (Necturus maciilosus) and hell- 

 benders (Cryptohranchus alleganiensis) . Besides these are 

 numerous of our larger and predatory fresh-water fishes, which 

 often find them no doubt desired food. 



The females are usually difficult to determine specifically, and 

 where several species occur are only to be recognized pro- 

 visionally, unless found actually copulating. 



