CAVE FISHES OF NORTH AMERICA. 



383 



branes joined to the isthmus, sometimes loosely; bodj^ covered with 

 veiy small, irregular!}' arranged cycloid scales; no lateral line; vent 

 in the j^ouug located in the normal position, but in the adult far for- 



: rASf-^:^. 



Cut 8. — Internal anatomy of Amb!i/opsis spelceus. 1, anus; 2, opening of the oviduct; 3, oviduct; 

 4, ovary, which is single; 5, liver; 6, duodenum; 7, gall-sac; 8, pectoral fin; 9, one of the pyloric 

 coeca; 10, coecum; 11, stomach; 12, spleen; 13, air-bladder; Hand 16, intestine; 15, pancreas; L, liver. 



ward, just behind the angle of the union of the gill membranes. The 

 transition of the vent from what is its usual position in most fishes to 

 this unusual one just back of the gill openings takes place gradually 

 as the fish matures'^'; ventral fins wanting 

 except in Aniblyoj^sis^ xqv\ small in this 

 species; pectorals inserted rather high, mod- 

 erate in size; n-o spines in any of the fins; 

 dorsal and anal fins nearlj^ opposite; caudal 

 rounded or even pointed at the tip; no 

 median crest on the cranium; stomach coecal, 

 with 2 to 4 p^doric C(£ca; air-bladder well de- 

 veloped; ovary always single. Eggs caught 

 by the gills when spawned, at least in Amhh/opsis, and held there 

 until hatched; 3'oung remain in the gills in A/nhlf/ojysis until about 

 four-tenths of an inch long.^ 



«In a specimen of Aiahlyopsis 1.26 inches Ion" the anus is just below the insertion 

 of the pectorals. In a specimen 1 inch long it is nearer the ventrals than the pec- 

 torals. In a specimen of Typhlichthys 1.1 inch long the anus is well in front of the 

 pectorals, Ijut a short distance behind the gill. — Eigenmann, Pop. Sci. Mo., LVI, 

 1900, 485. 



^ Eigenmann, Marine Biological Lectures, 1899, 313. 



Alimentary canal of Tivg- 

 lichthys rosx. 



