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teeth triangular, acute, measuring one-fifth the length of the rostrum and directed as in Jons, 

 serratidigitus Cout. ; their internal margin runs obliquely outward and forward and makes a 

 right angle with the lateral margins of the rostrum. In the two other indopacific species, Jous. 

 latirostris Cout. and yous. crista fa Cout., the internal margin of these teeth runs straight 

 forward and makes an acute angle with the rostrum (H. Coutiere, Les " Alpheidae", 1899, 

 p. 71, Fig. 21 and 22). The upper surface of the carapace is glabrous. 



Antennular peduncle stout, the second article a little broader or wider than long, about 

 as long as the visible part of the first, third article one and a half as long as the second ; 

 distal margin of the articles a little setose. The stylocerite is subacute, extends to the middle of 

 third article and is hardly .shorter than the rostrum, while its outer margin is arcuate, convex. 

 Antennular flagella as in the other species of yousseatiiiua ; the undivided part of the outer 

 flagellum consists of one or two articles, inner branch about as long as the third antennular 

 article; first article of inner flagellum twice as long as thick and twice as long as the second. 



Carpocerite one and a half as long as thick at its distal extremity, reaching to the apex 

 of second antennular article, and much shorter than the antennal scale, which resembles that 

 of Jons, serratidigitus and appears as long as the antennular peduncle. Lower angle of the 

 basicerite dentiform, acute. 



Pterygostomian angle of the carapace rounded. The pleura of the i^' abdominal somite 

 extend by half their length over the carapace, those of the 6''' are immovable. Telson one- 

 third longer than the 6'^ somite, much narrowed backward, the length of the telson equals 

 4,5-times the width of the posterior margin ; proportion between the width at the base and 

 that of the posterior margin 2,3. Outer angles of the posterior margin acute, though not 

 prominent ; the margin is notched in the middle, the notch is t r a p e z i f o r m and its anterior 

 margin, which is less broad than the posterior, shows another very small, median incision. 

 At either side of this incision a long seta is implanted ; the posterior width of the notch 

 measures two-thirds the width of the lateral parts of the posterior margin. At either side of 

 the notch not four spinules are observed, as is the case in the other indopacific species of this 

 genus, but only two, of which the inner longer one is about as long as the posterior margin 

 is wide, while the other is half as long. Spinules of the upper surface small, measuring only Y„^ 

 the lergth of the telson ; they are placed not far from the lateral margins, the anterior pair 

 immediately behind the middle, the proportion between the length of the telson and the distance 

 of the anterior pair from the posterior margin being 2,3, the posterior pair just midway between 

 the anterior pair and the posterior margin. Uropods a little longer than the telson. 



The large cheliped, on the left side, is only present and is borne in the same position 

 as in yous. serratidigitus (H. Coutiere, I.e. p. 179, Fig. 212). The merus, which in this position 

 extends a little beyond the tip of the antennular peduncle, has a slender form; looked at 

 from the outer side it appears to become wider toward the distal extremity. This member 

 is not straight, as in yous. serratidigitus, but distinctly curved, the upper margin being 

 convex, the lower concave; the lower face of the merus is slightly concave with 

 the margins somewhat prominent and in the described position of the leg the merus apparently 

 embraces the convex, lower surface of the palm. The merus therefore functions hke in some 



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