12 POMOTIS RUBRICAUDA. 



Colour. The head is dusky above, and has often a greenish tint ; the opercles 

 and cheeks are red, with blotches or waving lines of pale blue running from the 

 upper lip towards the orbit ; the appendix of the opercle is dark, bordered above 

 and below with pale greenish-blue ; the body above the lateral line is more or less 

 dusky, with cupreous tints ; below the lateral line it is red ; the pectoral fin is 

 transjiarent, with a pale bluish tint at its posterior extremity ; the anal is of a 

 bluish colour near its tip, and has occasional cupreous spots at its base. The 

 caudal is dusky at its root, and reddish at its tip. 



Dimensions. Head one fourth the entire length of the animal ; elevation with- 

 out the dorsal fin equal to one head and a half; total length, eleven inches. 



Splanchnology. The peritoneum is silvery. The liver is large, and vi^ithout fissures on its inferior 

 face, though its left portion is longest and extends even behind the stomach. The gall-bladder is 

 in size and shape like a small olive ; its walls are thin, and the bile is very light-coloured. The 

 stomach is large, for, though small at first, it suddenly increases in dimensions, and, as the pyloric 

 portion goes off from its anterior part, it is so bent as to appear heart-shaped when distended ; the 

 pyloric valve is well developed ; the small intestine is at first very large, yet it soon decreases in 

 size and runs to the vent, whence it is reflected to the last coecal appendage, and then again turns 

 backwards to end in the rectum, which is less capacious and has no valve. There are seven coecal 

 appendages, increasing in length to the last, which is two inches long. The air-bladder is large, 

 as it extends not only the length of the abdominal cavity, but is prolonged in two broad horns for 

 an inch or more behind the vent ; it is rather heart-shaped in front, and has 4hin and silvery walls. 

 The kidney is well developed behind, though it is small in front. 



Habits. This fish lives with the Pomotis vulgaris, and feeds on the same prey, 

 but is always found in deep waters. 



Geographical Distribution. From Massachusetts to Georgia. 



General Remarks. The specific name " riihricauda," first imposed on this fish 

 by Dr. Storer, has here been retained, because it does not appear to me certain 

 that this animal is identical with the Pomotis ai^wndix ; for that is a much smaller 

 fish, with the body more arched, — its colour is dusky above and white below, — 

 its auricular appendix is always black, and has never a border of bluish-green, — 

 and it has only as yet been found in New York. 



