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4. Ptychognathus pusillus Heller. 



1865. Ptychognathus pusillus Heller. Reise "Novara", Crust., p. 60. 



1889. Ptychognathus pusillus de Man. Zool. Jahrb. Syst., Bd 4, p. 440. 



1S92. Ptychognathus pusillus de Man. Weber's zool. Erg. Reise niederl. Ost. -Indien, Bd 2, p. 325. 



1894. Ptychognathus pusillus Ortmann. Zool. Jahrb. Syst., Bd 7, p. 712. 



1895. Ptychognathus pusillus de Man. Zool. Jahrb., Syst., Bd 9, p. 99, Bd 10, 1S98, pi. 28, f. 22. 

 1900. Ptychognathus pusilla Alcock. Journ. As. Soc. Bengal, v. 69, pit 2, p. 405. 



1905. Ptychognathus pusillus de Man. Proc. Zool. Soc. London, 1905, p. 537, pi. 17, f. 1 — 5. 

 nee Ptychognathus pusillus de Man. Notes Leiden Mus., v. 5, 1883, p. 161, (= Pt. polleni 



de Man), 

 nee Ptychognathus pusillus de Man. Archiv. Naturgesch., Jahrg. 53, 1., 1888, p. 383 (= Pt. 



barbatus A. Milne-Edwards). 



Stat. 33. Bay of Pidjot, east coast of Lombok. 1 rf, in river. 



This species has been obscurely known till 1895, when de Man redescribed the type 

 specimen. Only in 1905 de Max made known the c? and his very detailed diagnosis renders 

 a fresh description useless. 



Pt. pusillus is, according to de Man, very nearly related to Pt. barbatus, but in the 

 former species the exognath of the external maxillipeds is narrower and in the Q does not even 

 attain the width of the ischium ; the carapace is more narrowed anteriorly and is somewhat 

 more granular; the anterior margin of the front is bordered by a doublé row of granules in 

 both species, but this row is continent in the middle in the case of Pt. barbatus, whereas in 

 Heller's species both rows are separated throughout l ). 



The present species ranges from the Nicobars to Christmas Island, Flores and even to f iji. 



The only specimen is not adult. The distance between the external orbital angles (8 mm.) 

 somewhat exceeds the Iength of the carapace (7.5 mm.), which is contrary to de Mans measure- 

 ments (1905, p. 541); the maximum breadth is 9.25 mm. 



5. PtychognatJnis guijulugani Rathbun. PI. 4, Fig. 6. 



1914. Ptychognathus guijulugani- Rathbun. Proc. U.S. Nat. Mus., v. 47, p. 71. 



Stat. 131. Karakelang, Talaut Islands. 1 cf. 



This small species, recently described by Miss Rathbun, has a much flattened, smooth 

 carapace, the various regions of which are scarcely separated one from another and none of 

 them inflated. The cervical groove is concave forward, scarcely distinct in the middle; cardiac, 

 intestinal and branchial regions are not separated off, the latter regions, as usual, declivous, 

 towards the postero-lateral angles of the carapace, but these sloping portions are not very 

 well defined above and bordered by a somewhat sharp ridge only in their posterior part. 

 Mesogastric area of a triangular shape; epigastric region divided by a faint but broad longi- 

 tudinal sulcus, parting from the interspace between the epigastric lobes; hepatical and branchial 



1) Kingsley (Proc. Ac. Nat. Sc. Philadelphia, 1S80, p. 204) declares the two species to be identical and records Pt. piisilhts 

 from Mauritius. 



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