6 



ARKIV FÖR ZOOLOGI. BAND 7. N:0 25 



in tbe conus, dextral and sinistral in position. The position 

 of the heart is shown in Fig. 4. 



Meckel^ mentions the heart of Balistes as an example 

 of Tjedemann's opinion that the shape of the heart is in 

 relation to the shape of the bodj^ being correct in many 

 cases. That is all that is hitherto known about the heart 

 of this fish. The species I have studied is B. vetula L. The 

 heart is very high and compressed. The auricle is very large 

 and quite dorsal in position to the ventricle. The auriculo- 

 ventricular communication is in the vertical plan, provided 

 with one anterior and one posterior similunar valve. The 

 CL ^ ventricle is cylindrical with 



a very thick muscular wall. 

 Betwen the ventricle and the 

 bulbus arteriosus there is a 

 very deep furrow indicating 

 the conus, in which we find 

 two semilunar valves, dextral 

 and sinistral in position. 



Ortkagoriscus is the only 

 Plectognath the heart of which 

 has been previously described. 

 According to Cuvier and Va- 

 lenctennes,- Plancus^ (1755) 

 seems to be the first to make 

 any statements on this sub- 



Fig. 5. Heart of Balistes vetula J^ct. I have not seen his 

 L. a vertical section ; h ventral view. paper. Other authors are Cu- 

 Reference letters as in Fig. 1. ^^^^^ MeCKEL, (1834), WeL- 



LENBERGH (1840), Stannius (1854), Harting (1865), Wahl- 

 gren (1868), Steenstrup and Lutken (1898). Meckel 

 writes : Alle im Herzbeutel erhaltenen Theile, Vorhof , Kammer 

 und Arterienstiel, sind hier kurz, hoch und rundlich. Der 

 Vorhof ist dreieckig und läuft gegen die Kammer in eine 

 obere und eine untere, kurze, stumfe, rundliche Verlängerung 

 aus; die Kammer ist fast so hoch als läng, oben sehr kurz, 

 unten weit länger, ziemlich breit, der Arterienstiel sehr ansehn- 

 lich ganz kugelförmig, plötzlich von der Arterie abgesetzt.» 



^ System der vergleichenden Anatomie. 5. Teil (1831) p. 152. 

 - Histoire nat. des poissons. Tom. 1. p. 509. 

 ^ Comm. bonon. t. II. pl. 11, p. 297. 



