562 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 45. 



tip of the uropods and being 1 mm. shorter than the extremity of 

 the terminal abdominal segment. 



All seven pairs of legs are prehensile. The last pair has the carpus 

 and merus dilated in rounded expansions on the inferior side. The 

 merus is short, being about one-third the length of the ischium. In 

 the last four pairs of legs these articles show an increasing expansion. 



Some of the specimens obtained are larger than the one figured 

 and described, but in most of these the abddmen is curled up at the 

 extremity. I have therefore taken the smallest one as the type. 

 The male differs from the female in size, being much smaller; in the 

 more symmetrical body, longer antennae, narrower 

 head, and smaller terminal segment of the abdomen. 



The type-specimens, male and female, were taken 

 from Acheilognailius cyonostigma (Jordan and Fowler), 

 found in Lake Biwa, and two males and two females 

 were taken from the same host at Omi, Lake Yogo. 

 Other specimens are as follows: A male and a female 

 fig. 6.— ichthy- on Acheilognathus lanceolatum (Schlegel) from Funa- 

 nensiT lake y a( lo, Kiusiu, Japan, and a male and a female on the 

 biwa, from same host from Omi, Lake Yogo; a male and a female 

 thu S EI cyono". 011 Acheilognathus tabira Jordan and Thompson, MSS., 

 stigma, sev- from Lake Biwa; one female on Gnathopogon elongata 

 female'^x 14?^ (Schlegel) from Lake Biwa; two males and two fe- 

 males from two specimens of Acfieilognathus rhombeum 

 (Schlegel) from Lake Biwa; two males and two females from Acfiei- 

 lognathus limbatum Jordan and Snyder from Lake Biwa. 



This species differs from /. jellinghausii in the larger eyes, the 

 larger and more circular form of the terminal segment of the abdo- 

 men, the shorter uropoda, the shorter and differently shaped merus 

 of the seventh pair of legs, and the larger head and wider abdomen, 

 compared with the thorax. 



Type.— Cat. No. 45617, U.S.N.M. 



LIST OF REFERENCES. 



Herklots, J. A. Deux nouveaux genres de Crustaces vivant en parasites sur des 

 poissons-epichthys et ichthyoxenos. Archives Neerlandaises des Sciences 

 exactes et naturelles, vol. 5, 1870, pp. 120-137, pi. 5, La Haye. 



Ouwens, P. A. Nog lets over Ichthyoxenus jellinghausii (Herklots). Natuurkundig 

 Tijdschrift voor Nederlandsch-Indie, vol. 67, 1908, pp. 29-35, Weltevreden. 



S chiqs dte, J. C, and Meinert, Fr. Symbolae ad monographiam cymothoarum 

 crustaceorum isopodum familise. IV. Cymothoidse. Trib. II. Cymothoinae. 

 Trib. III. Livonecinse. Naturhistorisk Tidsskrift (3), vol. 14, 1884, pp. 221-421, 

 pis. 6-18, Kj0benhavn. 



Weber, Max. 1 Die Siisswasser-Crust. des Indischen Archipels, nebst bemerkungen 

 uber die Siisswasser-Fauna im Allgemeinen. Zool. Ergebnisse, vol. 2, 1892, pp. 

 557-560, pi. 30, fig. 1, Leiden. 



Willink, H. D. Tieenk. De "Songkeat" een vischparasiet. Natuurkundig Tijd- 

 schrift voor Nederlandsch-Indie, vol. 64, 1905, pp. 156-161, Amsterdam. 



1 1 have not been able to obtain this paper. 



