THOMPSON : A RAPE THALASSINID. 
3 
angle. In the female the abdominal segments measure, respectively, 
along the back, 2, 3, 3.8, 3.9, 5, 3.3, and 4.7 millimeters. 
Eyes on short peduncles, not visible from above; a minute pig¬ 
ment iieck. 
Antennulae (pi. 1, fig. 2) with short tapering flagella; inner 
about half length of outer; in female shrimp, inner of about twelve, 
outer of fourteen joints ; flagella of male broken ; peduncle smooth, 
with fine hairs, first joint longest, distal joint not especially elongate, 
flattened dorso-ventrally. 
Antennae (pi. 1, figs. 2, 4) with an ovate scale, whose tip reaches 
middle of distal joint of peduncle; surface of scale tuberculate like 
carapace, unequally divided by a keel; outer border serrate, both 
borders hairy. The peduncle consists of five subequal joints; sur¬ 
faces tuberculate ; apical borders of the two distal joints, toothed; 
flagellum present in female specimen, 24 mm. long, tapering. 
Mandibles (pi. 1, fig. 6) probably subequal or equal in size, deeply 
excavate; borders thin, external serrate, internal with few scattered 
teeth; palpus two-jointed (the proximal joint may represent two 
fused joints), outer joint “with simple hairs on its inner, and stiff 
bristles on its outer margin.” 
First maxillae (pi. 1, fig. 7) with membranous, inflected, inner 
lacinia; palpus with moderate, naked flagellum, tip blunt. 
Second maxillae (pi. 1, fig. 8) with narrowly divided inner and 
outer laciniae; endopod slender, hirsute, almost as long as inner 
lacinia; scaphognathite broad, membranous, produced at posterior 
angle and with tuft of hairs at the apex of the angle. 
First maxilliped (pi. 1, fig. 10) with apex of endopod expanded, 
triangular, membranous, exceeding lacinia interna; peduncle calci¬ 
fied, cylindric ; flagellum of exopod long, first joint nearly equaling 
outer joints taken together, peduncular joint expanded. 
Second maxilliped (pi. 1, fig. 9) pediform; endopod with outer 
angle of penultimate joint produced; peduncle of exopod attaining 
tip of endopod, flagellum nearly equaling peduncle. 
Third maxilliped (pi. 1, fig. 5) pediform; basal joint of endopod 
excavate, serrate on inner border; face of fourth joint with a series 
of transverse rows of short, stiff bristles (pi. 2, fig. 26) ; exopod 
attaining fourth joint of endopod. 
Pereiopods with ischio-basis joint visible as in Axius stirynchus ; 
without exopods; smooth; bases of first pair approximate, bases of 
