MORPHOLOGY OF CYPRINODONT FISHES. 



3 



part, tapering forwards, that has thick glandular walls. There 

 is no trace of a pneumatic diict. 



The short oesophagus leads into the stomach, which is simple, 

 without csecum or pyloric appendages ; the intestine forms a 

 single coil just in front of the air-bladder, and then runs down- 

 wards and forwards to the anus. The liver is large, and there 

 is a well-developed spleen situated on the anterior part of the 

 intestinal coil. 



The kidneys extend from below the basioccipital to the posterior 

 end of the abdominal cavity ; they are paired, but not enlarged, 

 anteriorly, unpaii-ed posteriorly ; the ureters leave the kidneys 



Text-figure 1. 



JSfeostethus lankesteri, ? . Part of head and abdominal region cleared and viewed 

 as a transparent object (X 10). The ovary is clearly visible, lying in front of 

 the air-bladder and below the alimentarj^ canal. 



Ji., heart ; a., anus ; p., postanal papilke ; o., opening of the oviduct ; u., opening of 

 ureter. 



above the anterior part of the air-bladder and soon unite to 

 form a single duct that runs downwards and forwards below 

 the intestine. The ovary is unpaired and lies in front of the 

 air-bladder and below the intestine ; it narrows forwards, and 

 the very short oviduct arises from its anterior end. The ova are 

 comparatively few and large. 



Except for modifications correlated with the thoracic jDosition 

 of the anus and urino-genital apertiu-es, e. g. that the air-bladder 

 is posterior instead of superior, the intestine runs forwards instead 

 of backwards, etc., the visceral anatomy is essentially similar to 

 that of the Fundulinse. 



