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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXV. 



that in one example the eyes are entirely gone while in the others the 

 eyes are present, but very small. Dr. Packard has called attention 

 to the well-developed eyes; compared with other subterranean species 

 they may be regarded as well developed, but when compared with the 

 Gammams in the pool just outside the cave their eyes are minute and 

 not more than rudimentary. In the living animal a great variation 

 was observable in the color, some being pure white while others were 

 inclined toward the purplish spoken of b}^ Packard. The original 

 description of C. antennatuH is here quoted, ]>ut it must be understood 

 that the identification of my specimens with Packard's species has been 

 on account of the correspondence of his figure and typo locality rather 

 than the description. 



It is a large and purplish species; the first anteniipe very long; the flagellum with 

 20 to 2-t joints; the entire antennfe being over one-half and nearly two-thirds as 

 long as the body; the last joint of the peduncle being slightly more than lialtas long 

 as the penultimate joint. Compared with C. (/racilis Smith, from Lake Superior, it 

 differs in the form of the eyes, the longer and stouter tirst antenn;e, the flagellum 



II.— Crangonyx antennatum. 



b Head with base of upper and lower antennie and eyes, 

 c Manus of second pair of feet, .\fter Pacliard. 



having a greater number of joints, and in the different proportions of the joints of 

 the peduncle. * * * The fourth pair of epimera are usually large and square. 

 The telson, together with the caudal stylets, is much as in C. gmcUts, but the rami 

 are slightly stouter and more polished and the spinules a little stouter. It is prob- 

 ably a little larger species than C. gracilis, the specimens being 6 to 7 mm. in length; 

 the eyes are not so distinct and are only one-fourth as large as in C. (jraciiis. 



1 first met with this crustacean well within the cave and beyond the 

 point where the last traces of daylight were visible. They were found 

 on a piece of decaying wood, but, although a number were seen, they 

 were so active that only a few were olitained for preservation. I 

 afterwards found them in various parts of the cave stream, always 

 on decaying wood. 



Although there are several rather important differences between my 

 specimens and the description of O. antciiiiatunt^ I have no hesitation 

 in regarding it as Packard's species, as it agrees ver}' well with the 

 figures, l^ut 1 find it nmst belong to the genus NiplianjaH of Schiodte 

 rather than to Crangonyx. 



