166 Apodal Fishes of Bengal. 



possessed of this peculiarity are without any air-vessel,* but 

 they have all an extremely elongated liver, either extended 

 to, or situated at the posterior extremity of the abdomen. 



The heart is enclosed within a strong serous membrane 

 or pericardium, which is united externally to the parieties of 

 the thorax, forming a partition between that cavity and the 

 abdomen. The heart is fixed within the pericardium merely 

 by the great blood vessels passing to and from it. It is of a short 

 compact oval figure generally in Anguilliformes, but larger, 

 more oblong and pointed at the extremities in Ophicardides. 

 In the former the branchial vessels generally pass directly to 

 and from the apex of the heart ; in the latter they seem to 

 pass with the great aortic and venous vessels which enter 

 and emerge about the middle of the heart between that 

 organ and the spine. The heart consists generally of a sin- 

 gle ventricle and auricle. In some the ventricle appears to 

 be double, as in Ophicardia Phayriana ; in others the auricle 

 performs the function likewise of a ventricle, transmitting 

 a portion of the blood by the branchial arteries to the gills, 

 as in those cases in which the branchial vessels emerge from 

 the apex of the heart. 



9. With regard to the gills; in some these are fully de- 

 veloped as in ordinary fishes, consisting of pectinated combs 

 supported by smooth bony arches. In others, the gills re- 

 taining their pectinated form, have lost the bony arches 

 which ordinarily support them. In others, the bony arches 

 are indeed found as naked symbols, but without function 

 or use, having no gills strictly speaking, or pectinated bran- 

 chial combs attached to them. 



Thus oscillating as it were between fishes and amphibia, 

 they preserve the decided characteristics of the former, pre- 

 senting at the same time, many decided relations to the latter. 

 The want of pectinated gills is compensated for by means of 



* Cuvier assigns this organ to the genus Synbranchus, Bl. We do not however 

 find it in any of the East India Ophicardians. 



