164 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
c. Telson and uropods forming a caudal fan (except in Branchuropus) Tribe Flabeelifera 
il. Pleon consisting of six free segments; uropods with both branches freely articulated with peduncle. 
e. Maxiliipeds with the “palp” free, the margins of the last two joints more or less setose, never 
furnished with hooks. 
First maxillae with the plate of the third joint tolerably broad, at least toward the middle. 
/. Mandibles with the distal half stout, very conspicuous, uncovered, or with only the anterior 
margin concealed; from the base toward the middle directed forward and a little . 
outward. 
y. Mandibles with the rather broad, more or less tridentate cutting edges meeting squarely behind 
the large upper lip; the secondary plate and peculiar equivalent for the molar well 
developed. 
First maxiUce having the plate of first joint armed with three spines, that of third with many. 
Second maxilla; of moderate size, the three free plates very setose. 
Maxiliipeds with the “palp” rather broad, very setose Ciroi, akims 
tig. Mandibles with the distal part produced into a long prominent process, the pair much over- 
lapping; the secondary plate and molar evanescent. 
First maxillse having the plate of first joint unaTmed, of the third carrying one very long spine. 
Second maxillae small and feeble, the free plates almost rudimentary with few setae. 
Maxiliipeds with “palp” narrowed, not very setose (the antepenultimate joint rather elon- 
gate) Coram.anid® 
ff. Mandibles with the distal half narrow, most or all of it concealed by the upper and lower lips; 
from the base toward the apex directed gradually inward. 
First maxillse having plate of first joint unarmed, of third carrying two spines or only one. 
Second maxillse feeble, sometimes very small, with one plate or none, the setse very few or 
none. 
Maxiliipeds with the “ palp” rather broad, with no elongate joint Ai.cironid® 
ec. Maxiliipeds with the “palp” embracing the cone formed by the distal parts of mouth organs, 
the inner upper margin and apex never setose, the apex and sometimes the 
inner upper margin, at least in the males and the females without eggs, being 
furnished with outward-curved hooks. 
First maxillse with the plate of the third joint narrow throughout. 
Distal parts of the mouth organs forming a short subvertical cone. 
Second maxillse large, elongate, and proportionately broad, with two apical plates furnished 
with hooks. 
Maxiliipeds with the fourth and fifth joints sometimes coalesced, never forming a long joint. 
h. Mandibles with the secondary plate very often (perhaps always) visible; the “palp” with no 
inflated joint. 
Maxiliipeds commonly 7-jointed, sometimes 4-jointed, the last joint in the latter case rather 
short, obtuse TEgid® 
hh. Mandibles with no secondary plate; the “ palp ” in the adults with the first joint or both first 
and second joints inflated. 
Maxiliipeds always foui’-jointed, the last joint rather long and narrow, subacute Cymothoid® 
dd. First five segments of pleon fused; one branch of uropods immovably fused with peduncle Sph/ekomidyE 
cc. Uropods folding beneath the pleon to cover the pleopods Tribe Valvifera 
Only family represented Idoteid® 
ccr. Uropods terminal, various, sometimes filiform or conical, sometimes valvate, but never covering more 
than the last two segments of abdomen below. First antennse with three short 
joints, or fewer, or wanting Tribe Oniscoidea 
t. First maxillse with three setse on inner plate. (In the one genus from Porto Rico the second 
antennse multi-articulate) Ligiid® 
it. First maxillse with two setse on inner plate. (In the one genus from Porto Rico the second 
antennse tri-articulate Oniscid® 
Tribe CHELIFERA. 
APSEUDIDT. 
Apseudes espinosus, new species. 
Ceplialothorax short, less than length of first 3 segments of thorax, slightly wider than long; 
rostrum short, produced to a mere point; eye-stalks short, projecting' but slightly beyond sides of head. 
First 3 segments of thorax.su hequal to one another in length and breadth, approximately equal to head 
in breadth. Last 3 segments narrower; fourth segment longer than segments 2 and 3 combined; fifth 
free segment about equal to them; sixth segment about three-fourths as long as fifth. Epimera of first 
3 segments not evident, none of the segments with lateral spines; epimera of last 3 segments small, in 
dorsal view projecting slightly from beneath each segment near its articulation with its successor. Abdo- 
