190 ORTHRAGORISCUS. 



Breadth of the anal fin measured at the root. . M. 0.35 

 Distance between the tip of the upper jaw and 



the anterior part of the root of the pectoral fin. M. 0.67 

 Distance between the tip of the upper jaw and 



the centre of the eye M. 0.30 



Horizontal diameter of the eye M. 0.08^ 



Vertical diameter of the eye M. 0.07 



Greatest thickness measured between the pectoral 



fins M. 0.45 



Thickness measured just behind the pectoral fins. M. 0.42 



Breadth of the pectoral fin measured at its root. M. 0.21 



The weight of the liver amounted to 68 kilograms , whilst 

 the ovarium (our specimen is a female) weighed 4.5 kilo- 

 grams. The diameter of the best developed eggs varied 

 between 0.42 ra.m. and 0.45 m.m. 



There was hardly any trace of asymmetry, as found by 

 Prof. Harting with Ortkragoriscus ozodura ^). 



On trying to determine the species into which this 

 Sun-fish has to be classed, we meet with great difficulties; 

 for whilst ichthyologists as Günther and Day class all 

 specimens of Ortkragoriscus into 2 or 3 species, viz. 0. 

 mola, 0. lanceolatus and 0. truncatus , the first of which 

 only is said to be found on our coast, Ranzani divided 

 them into 6 genera and 15 species. This is to be accounted 

 for that Ranzani made his classification ^) after an exami- 

 nation of stuffed specimens, or of the description of those 

 stufied specimens, which examination he carried on in no 

 critical manner , as is now generally acknowledged , even 

 by Italian ichthyologists. 



It must be owned that descriptions or drawings made 

 from live or fresh specimens are, comparatively speaking, 

 rare. Among these are to be mentioned : A. J. Retzius' 



1) P. Ilarting, Notices zoölogiques , anatomiques et histiologiques sur I'Or- 

 thragoriscus ozodura. Utrecht, 1865. 



2) Ranzani, Nov. Comm. Ac. Sc. Inst. Bonoa. Ill, 1839, p. 80. 



JVotes from the Leyden ]Miiseuiii, Vol. X!I1. 



