FEOM THE INLAND SEA OF JAPAN. 389 



Lambeus (Oncodolambrus) PEiEDATOR*, de Man. (PI. 31. figs. 1-3.) 

 Lamhrus [Oncodulambrus) pradator, de Man^ in Ann. & Mag. Nat. Hist. ser. 7, vol. xvii. 1906, p. 400. 



One male from Japan, the locality not defined. 



Probably a species of small size. Measured in the middle line the carapace appears to 

 be 7 mm. long, the front included, and the greatest breadth at the angles between the 

 antero- and postero-lateral borders measures 10 mm. : the broadly triangular carapace is 

 thus nearly once and a half as broad as long. The triangular, subacute front is 

 prominent, but strongly, obliquely, deflexed. The lateral margins are parallel, though 

 slightly concave, between the eyes and then curve inward ; they are smooth and entire, 

 but, on 6:1 cli side, the subfrontal process is visible as a small tooth or prominence, Avhen 

 the front is looked at from above, the subfrontal process being situated almost as 

 far distant from the tip of the rostrum as from a transverse line that runs along the 

 posterior border of the orbits. The breadth (1'8 mm.) of the front at its base is almost 

 one-fifth of the greatest breadth of the carapace. The smooth iipper surface of the front 

 is concave between the eyes ; the groove, here rather broad and deep, becomes gradually 

 more shallow anteriorly ; the groove gradually narrows backward on the upper surface 

 of the somewhat elevated gastric region until its posterior end, when one observes a low 

 rounded tubercle in the middle line. 



The gastric region is slightly inclined from behind forwards. A little in front of the 

 round tubercle the gastric region carries, on either side of the middle line, another obtuse 

 tubercle that is much smaller and much less prominent. The cardiac region carries, in 

 the middle line, two obtuse tubercles one behind the other, which are as large as the 

 tubercle at the posterior end of the gastric region ; the anterior cardiac tubercle is once 

 and a half as far distant from the gastric tubercle as are the two cardiac from one another. 

 Behind these prominences, which are, however, not so high as the swollen, branchial 

 regions, one observes, on the posterior slope of the cardiac region, two other smaller 

 tubercles, the anterior of which is probably double. The slightly convex and granulated 

 posterior margin of the carapace carries five tubercles, namely, in the middle three 

 smaller ones, of which the median one is a little larger than the two others and are 

 contiguous to one another, and a larger tubercle on each side more laterally. The 

 tubercles of the gastric and cardiac regions as also those of the posterior border of 

 the carapace appear granulated under a very strong lens. The intestinal region carries, 

 on each side, in the angle between the cardiac and branchial regions, two very low 

 prominences, separated by a shallow groove, the anterior being somewhat larger than 

 the other. 



The distance between the external orbital angles, which are not at all prominent, 

 measures almost one-third of the greatest breadth of the carapace. The hepatic area* 

 situated between the orbits and the swollen, branchial regions are deeply concave ; they 

 are smooth, like the gastric and branchial regions, but finely punctate, the punctuation 

 being more crowded on the gastric region. The considerahly swollen and Infiated 



* Prctdator, robber : because, when looked at from in front, the crab seems to be burdened on each side with 

 its prey. 



56* 



