150 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
EXPLANATION OF THE PLATES. 
Plate I. 
Fig. 1. Cauloxenus stygius Cope.—la, 16, lc, the same in different positions; a, 6, antennae; o, mandible (?); a:, point of 
attachment of arms to its host. Highly magnified. 
Fig. 2. Canthocamptus cavernarum Pack.—2a, head, showing the antennules and antennae; st., stomach; 26, the second 
antennae, more magnified; 2c, end of the body, dorsal view; 2d, the same, enlarged. Author del. 
Plate II. 
Fig. 1. Asellus communis, from Indiana.—Antennule (first antenna); la, end of the same, showing the three olfactory 
rods; 16, lc, mandibles, with palpus {palp. ); Id, le, first maxilla (?) (compare PI. Ill, fig. 2i); If, first maxilla 
of authors; 1 g, second maxilla; 16, the same, incompletely drawn ; li, maxillipede; st., stipes ; l.l., lateral 
lobe; palp., palpus; lab.,lobe of the labium ; *, delicate membranous processes connecting the opposing 
edges of the labial lobes; 1 j, first pair of male genital armature ; 1 Tc, second or last pair of male genital 
armature; ! I, penis. 
Fig. 2. Asellus intermedins Forbes (drawn from specimens labeled by him).—Antennule; 2a, second joint of the 
same, showing two auditory setae; 25, end of the same, showing three olfactory rods, the terminal joint 
ending in three setae (one broken off); 2c, auditory setae; 2e, an olfactory rod ; 2 f, one of the last uropoda, 
the set® unusually long and numerous in this species. 
Fig. 3. Asellus brevicauda Forbes (drawn from specimens labeled by him).—Antennule; 3a, second joint of the same, 
with four auditory set®; 35, end of the same, with three olfactory rods ; 3c, a leg of the first pair, male; 
3d, a uropod of the last pair (its mate was much shorter). Author del. 
Plate III. 
Fig. 1. Cascidotcea stygia Pack. Drawn by J. S. Kingsley from a specimen exactly like one from Mammoth Cave; 
the details drawn fsom a Mammoth Cave specimen, la, larger antenna; 16, cercopod, 2 ; lc, cercopod, £; 
Id, one of the terminal set®, much larger than the others and bulbous at the end. 
Fig. 2a. C. sl’ygia.— Antennule of short form from the Labyrinth, Mammoth Cave; 26, end of 2a, with the three olfac¬ 
tory rods; 2c, 2 antennule; ol., olfactory rods; 2d, the same, enlarged, showing the four terminal joints filled 
with nerve cells {n. cells), and the auditory bristle {and. s) ; 2e, first maxilla (of authors); 2 f, the same 
enlarged, the outer lobe bearing ten or eleven simple set®, the inner lobe five spinulated set® ; 2g, second 
maxilla (of authors); 2ft, end of same, enlarged, each of the two outer lobes bearing on the inner edge six 
or seven curious comb like set® (not very well represented in the plate), the other set® transversely stri¬ 
ated ; 2i, the second pair of appendages behind the mandibles (first maxilla ?). 
Fig. 3, 3a. C. stygia Forbes, from a weli in Illinois.—Second joint of antennule, with three auditory bristles; 3a', three 
basal joints of antennule from a Mammoth Cave individual, with an auditory bristle on the basal and two 
on the second joint. 
Fig. 4. C. stygia, from Annville, Pennsylvania.—Antennule of seventeen joints—4a, end of the same, with six olfac¬ 
tory rods, three of which are on the sixth joint from the end. 
Fig. 5. C. stygia, from Long Cave.—Antennule; 5a, antennule of another individual from the same cave, with but 
eight joints; 56,5c, antenn® of the same; 5d, a leg of the first pair, 2 adult, with eggs. 
Fig. 6. C. stygia, collected in daylight, 50 feet in from entrance of Walnut Hill Spring Cave, attennule; 6a, terminal 
joints of the same. 
Fig. 7. C. stygia, from Bradford Cave.—Antennule of ten to eleven joints. 
Fig. 8. C. stygia, from Carter (X) Cave—8a, terminal joints of the antennule, with five olfactory rods. 
Fig. 9. C. nickajackensis. —Antennule; 9a, terminal joints. 
All the figures except one drawn by the author. 
Plate IY. 
Fig. 1. Ccecidotcea stygia Pack., from Mammoth Cave.— 2 mandibles (inside) ; la, right mandible (on the outside) ; m, 
muscles; palp., palpus; 15, maxillipede; st., stipes; l.l., lateral lobe ; palp., palpus ; (aft., labium; lc, labium 
and palpus of 16; Id, one of the first pair of feet, £ ; le, the same, 2 ; 1/, seventh leg, $; 1 g, the same, 2 i 17b 
first abdominal legs, $; li, one of the second pair, $; 1 j, under side of abdomen, $ ; 1ft, the coupling organs, 
magnified; x, claspers; II, underside of abdomen, 2; 1 m, the same with the outer appendages removed. 
