vol. 

 189: 



y^,y''] PROCEEDING H OF THE NATIONAL MLTSEUM. 101 



one on either side posteriorly. There is a sharp tubercle on each side 

 at the hepatic region, and a short, sharp spine, extending horizontally 

 and somewhat curving' forAvard, at the summit of each branchial region. 

 Cardiac and intestinal regions rather small and only moderately ele- 

 vated. Posterior margin with a slightly prominent tubercle at the 

 middle. Kostrum scarcely as long as broad, laminiform, scarcely con- 

 tracted at base; horns shorter and less acuminate than in *S'. aouti/rons. 

 Pra'orbital tooth prominent and acute, but rather short. Parts about 

 the head below much as in S. avutifrons. The tooth forming the ex- 

 ternal angle of the orbit is deeply concave below, leaving the orbit at 

 that point widely interrupted. Margin of the pterygostomian region 

 with three small, obtuse, lobe-like teeth; a deep sinus separates this 

 margin from that of the side of the carapax. Feet all much compressed. 

 Merus of chelopoda four-sided or prismatic, obtusely tuberculated 

 along the angles; superior edge with blunt teeth near the base, and 

 one prominent sharp tooth near the extremity, being one of three large 

 teeth surrounding the insertion of the carpus. Superior and inferior 

 edges of ambulatory feet somewhat setose; the penultimate joints of 

 these feet, however, are smooth and slender. In this and the other 

 known species of the genus the seta^ are stout and clavate in form. 

 Tlie dimensions of a sterile female are: Length of carapax, (>.()5; 

 greatest breadth, 0.51 inch. 



This si)ecies was dredged in the Harbor of ITakodadi, Island of Jesso, 

 Japan, on a bottom of weedy sand, at the depth of fathoms. 



Only one other spe(;ies of the genus is known, ti. acutifrons Dana, 

 which inhabits the opposite coast of the ISTorth Pacific. 



Dione affinis «Io Haaii.* 



The only specimen taken is young; the dimensions of the carapax 

 being, length, 0.57; greatest breadth, 0.41; breadth between pr.eor- 

 bital spines, 0.35 inch. Proportion of this interorbital breadth to the 

 length, 1: 1.03. This proportion, in de Haan's figure, is 1 : 1.03. Our 

 specimen differs from those described by de llaan in its more depressed 

 form, its narrower and smoother carapax and broader front. There is no 

 tooth within at the base of the movable finger, and none on the outer 

 base of the hand. The horns of the rostrum are longer than in the 

 adult i>. afinin, and the abdomen of the male is not dilated near the 

 base. 



Having no opportunities of (;omparing <mr specimen with the young 

 of the species to which it is here referred, we do not venture to con- 

 sider it distinct. 



It was taken in a harbor on the northwest coast of the Island of 

 Ousima. 



^Equivalent to Schicojyhrijs osixni (Milne Edwards). See \rAg^ 91. — M. J. R. 



