20 
PACIFIC SCIENCE, Vol. VII, January, 1953 
plete and because of the dubious worth of the 
exopodites as a diagnostic character, it has 
seemed advisable not to create a new genus 
for this specimen. When another specimen, 
complete with the large chelipeds, is found it 
may be necessary to remove this species from 
this genus. 
relationship: If A. hiunguiculatus belongs 
to this genus, it can be separated from all 
other species by the lack of articulated pleura 
on the sixth abdominal segment; it can be 
separated from all species save A. fissipes Cou- 
tiere by the presence of the biunguiculate dac- 
tyli on the third to fifth legs, and from A. fis- 
sipes (Coutiere, 1908, and more completely, 
1921), by the characteristics presented in the 
following tabulation: 
A. hiunguiculatus 
Rostral tip without hairs 
Stylocerite shorter than 
first antennular article 
Carpocerite shorter than 
antennular peduncle 
Terminal article of third 
maxillipeds with bristles 
Ratio of carpal articles of 
second legs 10 : 8 : 6 : 
6 ; 10 
Ratio of articles of third 
legs: ischium, 0.75; me- 
rus, 2.1; carpus, 1.0; pro- 
podus, 2.3 
A. fissipes 
Rostral tip with hairs 
Stylocerite almost as long 
as second antennular 
article 
Carpocerite longer than 
antennular peduncle 
Terminal article of third 
maxillipeds without 
bristles 
Ratio of carpal articles of 
second legs 10 : 5 : 5 : 
4 ; 6 
Ratio of articles of third 
legs: ischium, 0.8; me- 
rus, 1.4; carpus, 1.0; 
propodus, 1.6 
Neoalpheopsis gen. nov. 
Carapace projecting to form rostrum and 
orbital teeth which obscure eyes, in dorsal 
view; corneas may or may not extend slightly 
beyond edge of carapace in lateral view. No 
pterygostomial tooth or even acute angle. 
Antennule with heavy peduncle, basal ar- 
ticle nearly as long as both distal articles. Sty- 
locerite broad, acute tip reaching distal por- 
tion of second antennular article. Inner flagel- 
lum as long as carapace, outer somewhat 
shorter and with setiferous bifurcation on ba- 
sal portion. 
Antenna with spine of basicerite broad, but 
apically acute. Scaphocerite broad, rounded 
with lateral spine not longer than squamous 
portion. Carpocerite normal. Flagellum al- 
most as long as body. 
Last article of third maxilliped with trans- 
verse rows of short setae on inner side, similar 
to that of Crangon. 
First pair of chelae well developed, large, 
approaching bilateral symmetry, without sex- 
ual dimorphism. Chela can be folded back 
against merus, merus triangular, somewhat 
excavate and twisted to accommodate chela; 
merus without spines or teeth. Carpus cyan- 
thiform, more elongate than in Crangon. Chela 
proper rounded, smooth, tapering, without 
crests or lobes, rotated so dactylus rests 
against merus when flexed. Cutting surface of 
dactylus with serrations that meet exactly 
with similar serrations on fixed finger, or de- 
veloped as knife-like ridge. Palmar and digital 
adhesive plaques poorly developed. 
Second legs with carpus of 5 articles, first 
secondary article slightly shorter than remain- 
ing 4 together. 
Third legs with proximal articles with mov- 
able spinules; propodus with few weak spines; 
dactylus simple. Fifth legs with usual brush 
oti inner side of propodus poorly developed. 
Abdomen of usual form. Pleura of sixth ab- 
dominal segment articulated. Uropods of 
usual form. Telson tapering, convex dorsally. 
Tip of telson with 2 pairs of spines, medial- 
ly to them margin projects markedly as acute 
triangle; triangle with 3 or 4 pairs of setiferous 
bristles. No anal tubercles. 
See Table 1 for branchial formula. 
This genus is distinguished from almost 
all other genera of crangonids by a series of 
characteristics, the more conspicuous of 
which are given here. 
It is distinguished from Athanas Leach, 
Athampsis Coutiere, Arete Stimpson, Areteopsis 
de Man, Automate de Man, Pterocaris Heller, 
and Ogyris Stimpson by the covering of the 
eyes, in dorsal view, by the projecting cara- 
pace; from Betaeus Dana and Parabetaeus Cou- 
tiere by the presence of a projecting rostrum; 
from Synalpheus Bate and Crangon Weber by 
