142 PROCEEDINGS OF THE NATIONAL MUSEUM vol. w 



ment of Conservation and director of the Alabama Museum of Nat- 

 ural History, who has generously provided me with material from 

 several caves in that State. Dr. Allan F. Archer, director of re- 

 search, Alabama Department of Conservation, has assisted both in 

 collecting the material and the data. I wish to express my thanks 

 to Dr. A. H. Wiebe, chief of the Biological Keadjustment Division, 

 forestry Relations Department, Tennessee Valley Authority, who 

 has been most cooperative during the course of this study. 



Genus CAMBARUS Erichson (1846) 

 Subgenus Faxonius Ortmann (1905) 



CAMBARUS (FAXONIUS) PELLUCIDUS AUSTRALIS, new subspecies 



Male I. — Body white, digestive tract dark. Rostrum with mar- 

 gins only slightly converging. Marginal spines short and acute. 

 Acumen long and slender. Upper surface of rostrum moderately 

 concave. Postorbital ridges with short acute spines. Sides of cara- 

 pace minutely granular. Cervical groove unbroken in front of five 

 or six lateral spines on each side. Spininess usually reduced from 

 typical G. pellucidus. Antennae as long as the body. Antennal 

 scale broadest anterior to the middle, with inner margin gently 

 rounded. Apical spine short; half the length of that of typical 

 C. pellucidus. Dorsal surface of chelipeds with small tubercles. 

 Tips of fingers sparingly setose. Hooks on the third walking legs 

 prominent, globose, and recurved. Hooks on the fourth walking 

 legs lacking. Gonopods reaching to the coxopodites of the third 

 walking legs. Rami short and nearly equal in length. Outer ramus, 

 with corneus tip, curved tightly around the inner ramus. Inner 

 ramus straight with slightly recurved slender fleshy tip. Setose 

 along tlie ventral line. 



Male II. — Hooks on the third walking legs recurved and rounded 

 but reduced in size. Gonopods with fleshy tips reaching to the 

 coxopodites of the third walking legs. Inner ramus a little more 

 inflated. 



Female. — Annulus ventralis contrasting sharply with that of typi- 

 cal G. pellucidus in that the large central hemispherical tubercle has 

 its greatest height on the anterior wall. The tubercle recedes pos- 

 teriorly and levels out to form a narrow flat border for the full 

 width of the annulus. A shallow median furrow marks the posterior 

 slope and becomes deeper and sinuate with a sharp curve to the 

 observer's right in the posterior margin. 



Variations. — I have placed in this subspecies a crayfish from sev- 

 eral caves in northern Alabama on the basis of identical genitalia. 

 However, there are slight variations from cave to cave. The num- 



