44 Bulletin Vanderhilt Marine Museum, Vol. V 



Distribution: Eastern Seas, (Fabricius) ; Indian Seas, (Linne) ; 

 Indian Ocean, (Latreille) ; South Seas, (Herbst) ; Amboina, (Rum- 

 phius; Herbst; Latreille); Sandwich Isles, (Herbst; Dixon; Bosc) ; 

 Japan, (De Haan) ; either Durban, South Africa, or Agulhas Bank, 

 Cape Colony, (Stebbing) ; Port Louis, Mauritius, (Bouvier). South- 

 port, Queensland, (Boone), " Sihoga" station 248, Rumah, Tiur Island, 

 East Indies, 36 meters depth, (Ihle). Mako, Pescadores Island; 

 Fukura, Sagami Bay, Japan, (Balss) ; Misaki, Sagami, Nagasaki, 

 Hizli, Japan, (Rathbun). 



Material examined : One very large specimen, collected at South- 

 port, Queensland, Australia, September 24, 1931, by the ^^Alva." 



Technical description : Carapace shield-shape, very convex from 

 side to side and moderately so fore and aft, with the frontal margin 

 deeply, irregularly serrate and three and two-fifths times as wide, 

 from tip to tip of the anterolateral spine, as the posterior margin. 

 The anterolateral width at this point is the maximum width of the 

 carapace, being slightly in excess of the width across from tip to tip 

 of the large tridentate frontal processes. The length of the carapace 

 from the tip of the rostral spine to the posterior margin is about 3 mm. 

 less than the maximum width. The maximum width is 133 mm. ; the 

 length in the median dorsal line is 130 mm. ; the length of the carapace 

 from the outer tip of the largest tridentate frontal process to the 

 posterior lateral angle is 150 mm. in a straight line measurement. 

 The entire dorsal surface is covered with elongate, squamose imbrica- 

 tions, whose triangulate or, in some instances rounded, apices are 

 forward-directed ; the posterior margin of these imbrications not being 

 well defined ; these imbrications are dorsally convex from side to side, 

 the anterior region of the carapace having them abundantly, but more 

 separated and usually of shorter length than those on the posterior 

 half, which are very closely spaced and on the average are about three, 

 or more than three times as long as wide. The frontal margin is 

 divided into seven lobes, a median lobe, which measured across its 

 base is equal to about one-fourth of the total width, and is produced 

 to a median triangulate rostral point on either side by a concavity 

 from the smaller, submedian triangulate tooth that marks the outer 

 angle of the median lobe, which is separated by a narrow U-shaped 

 sulcus from the next or innermost lobe, which basally is three-fifths 

 as wide as the median lobe and is composed of a crest-like lobe con- 

 sisting of three unequal, triangular teeth, the innermost and smallest 

 of these being slightly longer than the adjacent tooth of the median 



