[ 7 ] 



larger and with a large rounded and thick hand, all the feet with only one claw. 

 Rump with four large segments, without lateral appendages, but with the usual 

 ones beneath. Tail with short and recurved appendages. — It belongs to the fam- 

 ily Gammaria, the name was that of an ancient fluviatile God of Thessaly. 



39. Sperchius lucidus. Shining brown, eyes black, nearly round; appendages 

 of the tail shorter than the last article, curved outwards, with two articles and a 

 terminal filament. — Discovered in the springs and brooks near Lexington, Ky. 

 Length about one-third of 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. Lepleurus. Four antenna shorter than the head, nearly equal, trun- 

 cate, with a single segment. Body rather compressed and straight, with twelve 

 segments, all with a large lateral scale except the three anterior and the last, pos- 

 terior segments and scales longer. First pair of feet with a large oblong cheli- 

 form and cuspidate hand ; the second and third pair cylindrical pincifefous or 

 with two cylindrical and truncate fingers, the four other pairs slender ; all the 

 feet without real claws. Appendages beneath the rump almost similar to the 

 hind feet ; those of the tail short and with single segments. — Another fresh water 

 genus of Shrimps, of the family Gammaria. The name means lateral scales. 



40. Lepleurus rivularis . Olivaceous, eyes very faint irregular ; appendage of the 

 tail truncate straight obliqual ; antenna nearly horizontal, 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. LiRCEUS. Four antenna, the two upper ones very long, with four large 

 articles, increasing in size upwards, and many small ones ; the two lower antenna 

 shorter than the head and the fourth article of the long antenna, setaceous, adhe- 

 rent with the upper ones at their base. Head rounded, 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 a.n6.s\ih-ia.rm\.y Aselotia. The 

 name was that of a spring in Greece. 



41. Lirceus fontinalis. Blackish, upper antenna one-third of total length ; seg- 

 ments broader than the head and truncate lateraly, separated by deep clefts ; 

 back convex ; tail semitrilobe, margin hyalin, center raised longitudinally. — I de- 

 tected it in October 1819 in a spring near Lexington. It swims well ; feet short 

 with four articles, one of which is a claw ; the posterior ones longer and more 

 slender. Length one-fourth of an inch without the antenna ; breadth about one- 

 fourth of the length. Tail broad and twice as long as the head ; appendages short, 

 articulated, seldom jutting out of the utricule. 



VI CLASS. ENTOMIA.— THE INSECTS. 



VI. N. G. Selista. Body depressed, with nine segments, including the head 

 and tail. Head large ; forehead notched, ending in a large curved forceps with 

 a tooth inside. Two palps as long as the forceps, 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 two terminal threads Fourteen lat- 

 eral legs, with two articles and two claws besides, or bifid at the end. — A very sin- 

 gular genus of the family Myriapoda, and sub-family Scolop'endria. The name was 

 that of a nymph. 



42. Selista forceps. Fulvous brown, frontal forceps as long as the head, tail bi- 

 dentated. — Found near Baltimore by Mr. H. Hayden. It comes into the houses ; 

 length one inch. 



VII. N. G. Cryptomera. Body depressed, linear, narrow, with many segments, 

 each with one pair of lateral filiform legs with four articles ; alternate segments 

 shorter and almost entirely covered and concealed by the larger ones. Head 

 truncate ; eyes obsolete ; two long filiform multi articulated nearly lateral, and dis 

 tant antenna ; no visible palps. — It belongs to the family Myriapoda, sub-family 

 Chilognaihia, next to thegennsPolydesmus. The name means concealed parts. _ 



43. Cryptomera lunularis. Reddish brown ; sixteen pairs of legs, the last pair 

 longer; antenna one-third of total length; sides straight, tail short, lunulate; 

 length about one inch. — Found near Baltimore and Philadelphia on the ground: 

 segments as long than brOad. 



