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by a deep vertical septum into two channels, each channel being completed 

 below by a lamellar process from the first pair of maxillipeds. 



The external maxillipeds do not meet across the mouth, but leave exposed 

 between them the mandibles, and, in front of them, the afore-mentioned leaf- 

 like prolongations from the first pair of maxillipeds. 



The chelipeds are very large, and in flexion are closely apposed to the front 

 half of the carapace, so as to form a sort of buckler : the arm has near its distal 

 end, externally, a transverse wing-like expansion, complementary to the wing- 

 like expansions of the carapace : the hand is strongly compressed, its upper 

 border forming a high, sharply dentate or crenulate, crest. Except for the 

 fingers, the chelipeds are equal and symmetrical ; both the fingers, namely, of 

 one hand have on their outer aspect, near the base, a stout projecting lobule. 



The abdomen in the adult male consists of only five separate pieces, 

 owing to the fusion of the 3rd, 4th and 5th somites. In the young male, as in 

 the adult female, it consists of seven separate somites. 



Calappa exanthematOSa, Alcock and Anderson. 



Calappa exanthematosa, Aloook and Anderson, J. A. S. B. Vol. LXIII. pt. 2, 1894, p. 177, and 111. Zool. 

 Investigator, Crust, pi. xv. figs. 1, lo: Alcock, J. A. S. B. Vol. LXV. pt. 2, 1896, p. 146. ? = Calappa japonica, 

 Ortmann, Zool. Jahrb. Syst., etc. VI. 1892, p. 566. 



Extreme length of carapace a little more than two-thirds the extreme 

 breadth. 



The carapace is generally inflated, especially in the branchial regions : its 

 surface in rather more than its anterior half is covered with large round, or oval, 

 smooth mamillary tubercles having a red base and a shining yellow apex, and 

 exactly resembling smallpox pustules ; and is covered posteriorly with smaller 

 round, or oval, slightly elevated patches, which exactly resemble smallpox pa- 

 pules. The antero-lateral borders of the carapace are quite smooth in their 

 anterior half, and have 4 or -5 coarse serrations in their posterior half : the 

 posterior border is beaded, and is bounded on either side by a tooth. 



The clypeiform expansions are httle developed, their extreme transverse 

 dimension being less than one-third their extreme dimension in an inwardly 

 oblique antero-posterior direction : they consist of about seven serrated teeth. 



The pterygostomian regions have only a few scanty hairs. 



The front is bifid, the breadth of its tip is haK again that of the orbit, 

 beyond which it does not project. 



The flagellum of the antenna is nearly twice the breadth of the orbit in length. 



The endostomial septum is narrow, not extending vertically to the level of 

 the mouth, and quite plainly shows its origin out of a fold of the endostome : 

 its anterior border is cut straight, and projects obliquely. / 



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