188 M. Anton Stuxberg on new 
would belong at one time of its life to the one and at another 
time to the other. 
EXPLANATION OF PLATE XV. A. 
Fig. 1. Dexamine antarctica. 1a. Firstgnathopod. 16, Second gnatho- 
pod. lc. Third pereiopod. 1d. Hand and finger of third 
pereiopod, more highly magnified. 
Fig. 2. Seba Saundersit. 2a, First gnathopod. 206. Second gnathopod. 
2c. Fifth pereiopod. 
Fig. 3. Spheroma algoense. 3a. Underside of tail-piece. 
XXIV.—Deseriptions of some new North-American 
Lithobioide. By Anton STUXBERG. 
1. Lithobius monticola, n. sp. 
Lamina cephalica subcircularis, eadem fere latitudine ac lon- 
gitudine, margine postico subrecto, setis punctisque im- 
pressis sparse predita. Antenne mediocres, articulis 20 
maximam partem cylindraceis, setis rigidis vestitis compo- 
site. Oculi longitudine triplo majore quam altitudine, 
ocellis 7—9 in 2 series longitudinales digestis. Coxe pedum 
maxillarium secundi paris dentibus 6+ 6 conicis, acutiuscu- 
lis, nigerrimis armatee. Scuta dorsualia rugulosa, sparsis- 
sime pilosa, 2°, 4°, 6°, 7°, 9°, 11°, 13° margine postico recto, 
angulis posticis rectis vel rotundate rectangulis, 1°, 3°, 52, 
8°, 10°, 12°, 14° margine postico elevato sinuato, angulis 
parum productis, rotundate acuminatis. Scutwm ventrale 
158" fovea longitudinal: profundiore, cetera omnia plana. 
Port coxales numerosi, rotundi, in 3-4 series irregulares 
dispositi. Pedes primi paris calcaribus 2, 3,2.  Pedum 
analium articulus primus calcaribus binis, altero majore in- 
feriore, altero minore laterali armatus. Pedes anales ungue 
singulo, calearibus 1,4, 3, 1—1,4,3,2 armati. Color non 
manifestus. 
Longitudo corporis 18 millim. 
Hab. in Sierra Nevada (G. Eisen). 
2. Lithobius pusio, n. sp. 
Lamina cephalica subcircularis, eadem fere latitudine ac lon- 
gitudine, setis minimis sparsissimis. Antenne breviores, 
articulis 20 plerumque brevibus, crassis composite, ex 
quibus ultimus longissimus, longitudine quatuor prece- 
dentes junctos equans. Ocu/i ocellis 6 magnis in 2 series 
