[7] 
Tnrcjei- nr.cl with a large rounded and thick band, all the feet with only one claw. 
Rump witli four larg^e sej^ments, witliout lateral appendages, but with ti)e usual 
ones beneath. 'I'ail with short and recurved a})|)endag;es. — It belongs to the fam- 
ily Gammavia, the name was that of an ancient fluviatile God of Thessaly. 
59. Sperchiits litddus. Sliining brown, eyes black, nearly round ; appendages 
of the tail shorter tlian the last article, curved outwards, with two articles and a 
terminal filament. — Discovered in the springs and brooks near Lexington, Ky. 
T..engthaboutone-thirdof an inch, almost black when in the water, olivaceous 
brown when out of it, and pale when dry. Body arched, antenna descending. It 
swims well. 
IV. N. G. l,i:PLErnr>. Four anlonna shorter than the head, nearly equal, trun- 
cate, with a single segment. Body rather compressed and straight, with twelve 
segments, all witli a Large lateral scale except tlie three anterior and the last, pos- 
terior segments and scales longer. I'ii'st pair of feet with a large oblong cheli- 
form aiid cuspidate hand ; tiie second and third pair cylindrical pinciferotis or 
v/ith two cylindrical and truncate fingers, tlie four other pairs slender ; all the 
feet without real claws. Appendages beneath the rump almost similar to the 
hind feet ; those of the tail sliort and with single segments. — Anotlier fresh water 
genus of Shrimps, of the family Gcimmaria. The name means lateral scales. 
40. Lepleuriis rivtdaris. Olivaceous, eyes very faint irregular ; appendage oftlve 
tail truncate straight obliqual ; antenna nearly hori.':ontal, feet longer than the 
breadth of the body. — I have detected it in the brooks of the mountains of Penn- 
sylvania and at Shannon run, near Bedford Springs. Length about half an inch ; 
it crawls on the stones rather than swims or jumps. 
V N. G. LiitcErs. Four antenna, the two upper ones very long, with four large 
articles, increasing in size upwards, and many small ones ; tlie two lower antenna 
shorter tiian the head and the fourth article of the long antenna, setaceous, adhe- 
rent with the upper ones at their base. Mead roimded, eyes lateral and rounded. 
Feet with a single claw ; body pinnatifid with seven segments without lateral 
scales ; tail large, rounded, utriculated beneath, with concealed bifid appendages. 
This fresh water genus belongs to the family Oniscia and sub-family As^lotia. The 
name was that of a spring in Greece. 
41. LivceusfoiUinalh. Blackish, upper antenna one-third of total length ; seg- 
ments broader than the head and truncate lateraly, separated by deep clefts ; 
back convex ; tail semi'nlobe, margin iiyalin, center raised longitudinally. — I de- 
lected it in Octobe.r 1819 in a spring near Lexington. It swims well; feet short 
with four articles, one of v/hicij is a claw , the posterior ones I'T.ger and more 
slender. Length one-four'.h of an inch without the antenna ; iircadth about one- 
fourth of the length. Tail broad and twice as long as tiie head ; appendages short, 
articulated, seldom jutting out of the utricule. 
VI CLASS. ENTOMIA.--THE INSECTS. 
¥i. N.G Selista. Body deprsss'.'d. with nine segments, incTuding the head 
and tail. Head large ; forehead iiotchc-,', ending in a large curved forceps with 
a tooth inbide. Two palps as long as the to. ceps, with two articles and two claws 
at the end. Eyes lateral round ; antenna inserted before the eyes, as long as the 
frontal forceps, with two long segments and tv/o terminal threads Fourteen lat- 
eral legs, with two articles and two claws besides, or )iridat the end. — A very sin- 
gular genus of the family JMijriupoda, and sub-family Scolopendria. Tlie name wa% 
that of a nymph. 
42. Selistaforceps. Fidvous brown, frontal forceps as long as the headj tail bi- 
dentated. — Found near Baltimore by Mr. H. Hayden. It comes into the houses j 
length one inch. 
VII. N. G Cryptomera. Body depressed, linear, narrow, with many segments, 
each with one pair of lateral filitorm legs with four articles; alternate segments 
shorter and almost entirely covered ar>d concealed by the larger ones. Head 
truncate ; eyes obsolete ; two long filiform inulti articulated nearly lateral, and dis 
tant antenna; no visible palps. — It belongs to the family Myriapoda, siibflimily 
Chilo^nathin, next to the genus Polydesmits. The name means concealed ])arts. 
43. Cryptomera himdaris. Keddish brown ; sixteen pairs of legs, the last pair 
longer; antenna one-third of total length; sides straight, tail short, lunuiate; 
length about one inch.— Found near Baltimore and Philadelphia on the ground : 
segments as long than broad. 
