364 The Apodes, or Eel-like Fishes 
spicuous. The number of vertebrae is unusually large. The 
order contains the single family Monopteride, the rice-field eels, 
one species, Monopterus albus, being excessively common in 
pools and ditches from China and southern Japan to India. 
The eels of the suborder Holostomi (odds, complete; oropa, 
mouth) differ from these mainly in the separation of the shoulder- 
girdle from the skull, a step in the direction of the true eels. 
The Symbranchide are very close to the Monopteride in external 
appearance, small, dusky, eel-like inhabitants of sluggish ponds 
and rivers of tropical America and the East Indies. The gill- 
openings are confluent under the throat. Symbranchus mar- 
moratus ranges northward as far as Vera Cruz, having much the 
habit of the rice-field eel of Japan and China The Amphip- 
noide, with peculiar respiratory structures, abound in India. 
Amphipnous cuchia, according to Gunther, has but three gill- 
arches, with rudimentary lamina and very narrow slits. To 
supplement this insufficient branchial apparatus, a lung-like 
sac is developed on each side of the body behind the head, open- 
ing between the hyoid and the first branchial arch. The inte- 
rior of the sac is abundantly provided with blood-vessels, the 
arterial coming from the branchial arch, whilst those issuing 
from it unite to form the aorta. Amphipnous has rudimentary 
scales. The other Holostomt and Ichthyocephalt are naked and 
all lack the pectoral fin. 
The Chilobranchide are small sea-fishes from Australia, with 
the tail longer than the rest of the body, instead of much shorter 
as in the others. 
No forms allied to Symbranchus or Monopterus are recorded 
as fossils. 
Order Apodes, or True Eels. — In this group the shoulder- 
girdle is free from the skull, and the bones of the jaws are reduced 
in number, through coalescence of the parts. 
Three well-marked suborders may be recognized, groups per- 
haps worthy of still higher rank: Archenchelt, Enchelycephali, 
and Colocephalt. 
Suborder Archencheli.—The Archencheli, now entirely extinct, 
are apparently the parents of the eels, having, however, certain 
traits characteristic of the Isospondyll. They retain the sepa- 
rate caudal fin, with the ordinary hypural plate, and Professor 
