IOI 



to the length of the gastric region than in Nephr. Sibogae. In three of the four species the 

 cardiac region is traversed in the middle by a denticulated ridge, but in Nephr. Challengeri 

 this ridge is wanting cornpletely, the cardiac region being here smooth and unarmed. 



Nephr. japonicus Tapp. Can. is also a different species, which has pretty well been 

 figured in: Memorie della R. Accademia d. Scienze di Torino, Ser. II, T. XXVIII, 1873, but 

 the sculpture of the abdominal terga appears on that plate, at least in my copy of this paper, 

 rather indistinct. Prof. Döderlein of Strasburg has been so kind to send me for examination 

 2 of the 9 specimens of Nephr. japonicus from the Bay of Tokyo, mentioned by Dr. Ortmann in : 

 Zool. Jahrb. Abt. f. Syst. T. VI, 1891, p. 6. These specimens are an adult male long 212 mm. 

 and a somewhat younger female long 185 mm. Their examination proved in the first place 

 that the sculpture of the abdomen is e x a c 1 1 y the s a m e in the male and in 

 the female, so that the dimorphism, which was supposed by Ortmann (I. c. 1897) to occur 

 in this species, does in fact not exist. Dr. H. Balss, by whom several adult male and female 

 specimens of Nephr. japonicus were examined (1. c. p. 84), was also unable to find a dimorphism 

 with regard to the sculpture of the abdomen. As was already remarked above, the sculpture 

 of the abdomen has not been clearly figured on Tapparone Canefri's plate, but in Ortmann's 

 paper of 1897 (PI. 17, fig. 1) a lateral view of the abdomen of a female was publishecl, with 

 which the two cotypes of Nephr. japonicus, that are lying before me, fully agree. YYhen this 

 figure is now compared with the quoted figures of Nephr. andamanicus and with our male 

 from the Bali Sea, the sculpture of Nephr. japonicus appears more complicate: the raised band 

 along the posterior margin and the raised submedian parts of the upper surface of the terga 

 are in Nephr. japonicus grooved and subdivided, in Nephr. andamanicus not. 



In his quoted work of 19 14 Balss has figured on Plate I, fig. 2 an adult male of 

 Nephr. japonicus from Japan. Now I must ca 11 attent ion to the remarkable fact 

 that this figure closely resembles Nephr. andamanicus, except only as regard s 

 the large spin es at the base of the rostrum. In this figure indeed the abdominal 

 terga do not show the subdivision of the posterior and submedian raised parts of the upper 

 surface, described above: the sculpture therefore fully agrees with that of our male from 

 the Bali Sea, referred to Nephr. andamanicus and with the figures of this species in the 

 "Illustrat. Zool. Investigator". 



In Nephr. japonicus the 6 th somite of the abdomen carries in the middle line two 

 pairs of acute spin es, placed behind one another; these spines are clearly visible in 

 Tapparone Canefri's figure, like also in a lateral view in Ortmann's figure of 1897, and they 

 are also distinctly developed in the two cotypes from Strasburg. In the figure of Balss, 

 however, these spines seem to be wanting also! These two differences from the typical japonicus^ 

 shown by this figure, are for the present for me inexplicable. The rostrum indeed looks like 

 that of the typical japonicus, the large spines at the base reach the anterior margin of the 

 eyes and are clearly curved inward and downward like in japonicus, while in the male of 

 Nephr. andamanicus from the Bali Sea they extend only to the middle of the eyes and are 

 straight and turned outward ; the lateral ridges, posterior to the rostrum, seem to carry, however, 

 in the figure of Balss, only 3 spines, not 5 or 6 as in japonicus. The anterior pair of legs also 



