626 NOETH AMERICAN ASTACID.E FAXON. 



In the female tbe annulus ventralis is very protuberant, especially 

 the posterior border, and subcircular, with a deep central cavity. 



In young individuals tbe cbela and carpus are nearly destitute of tbe 

 tubercles found in full grown specimens. 



Length of a female, G5 mm ; cepbalotborax 31.5 mm ; from tip of rostrum 

 to cervical groove, 17 mm ; from cervical groove to posterior margin of 

 carapace, 14.5 ,um ; chela, 28 mm ; breadth of chela, 8 mm ; movable finger, 

 18 mm ; abdomen, 34 mm . 



The arrangement of the olfactory setoe on the outer flagellum of the 

 antenuules is similar to that in G. pellucidus, i. e., of the thirty seg- 

 ments of tbe flagellum, the sixteenth to the twenty-seventh bear olfac- 

 tory setse, and these setae are long, as in the other blind species of Cam- 

 barus. The peculiar pectination of the cutting edge of the fingers I 

 have not observed in any other species. 



From Wilson's <Jave and wells in Jasper County, Missouri. Miss 

 Eutb Hoppiu (M. 0. Z.). Three males, form I ; sixteen males, form 

 II ; fifteen females. 



The drainage of Jasper County, which lies in the southwestern part 

 of Missouri, goes to the westward and then southward by the Neosho 

 or Grand River into the Arkansas The following account of Wilson's 

 Cave and the wells from which this crayfish was taken, with remarks 

 on the habits of the animal, is extracted from Miss Hoppin's letters 

 printed in Mr. Samuel Garmau's paper on the cave animals of south- 

 western Missouri.* 



Wilson's Cave is about 50 feet long, nearly as wide, oven-shaped, and hgh enough 

 to stand erect except around the sides. The farmer had enlarged the entrance to use 

 the place as a creamery. A small very clear stream flowed along the left side, hav- 

 ing a width of 2 feet and a depth of 3, with a temperature of +54° F. About 10 

 feet from the entrance the light struck the stream in such a mauner that we could 

 see everything in the water without a lantern. The first things that caught the eye 

 were a lot of white crayfish, a dozen in all, like those I took from the wells. It 

 seemedasif I might take every oueof them. But, though blind, they have one or more 

 of the other senses very keenly developed. I am very sure they, as well as the white 

 fishes [Typhlichtkys subterraneua Gir.], have the tactile sense developed in an unusual 

 degree. At the least touch upon the water they dart away. As the net cautiously 

 follows, they escape adroitly, making no blunders as to the direction of the approach- 

 ing enemy, and hide in crevices of the jutting rocks or in the muddy bottom of 

 the stream. The mud was easily stirred so that nothing could be seen. These 

 creatures, fish aud crayfish, are only to be secured by patient waiting and skillful 

 management. The people at the cave say the fish never bite, and can not be taken 

 with hook and line. The crayfish were all found near the entrance, where there is 

 considerable light. Following the stream back to a dark recess, reached by crawl- 

 ing on the slippery rocks, the light of the lantern revealed a school of little white 

 fishes, such as I secured from the wells. All were very small. I saw half a dozen 

 or more, but secured only one. I concluded the crayfish liked the light. Perhaps 

 they remain near the entrance because they find there a supply of food. We found 

 a few snails floating about, but saw none iu the dark pool where the fish were. 



* Cave Animals from Southwestern Missouri. By Samuel Carman. Bull. Mus. 

 Comp. Zool., vol. xvn, No. 6, 18S9, pp. 225-240. 



