20 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



length is 0.15, and in the European specimens 0.15 and 0.1575 (Christi- 

 ania specimen). The smallest proportion is represented by specimens 

 from Massachusetts Bay and Halifax. 



(4) Teeth.— In number these are extremely variable. No. 12G85, ac- 

 cording to Gill, had on the blind side 17 above and 20 below, on the eye 

 side 6 above and 7 below. A Salem specimen, larger and older, had on 

 the blind side, above 26, below 28, on the eye side, above 13, below 14. 

 In young individuals, the teeth present the characters described by 

 Gill, having the teeth on the eyed side conical and separated. This 

 peculiarity disappears with age, all large specimens showing closely set 

 incisorial teeth upon both sides of each jaw. 



(5) Length of pectoral. — This is extremely variable within limits of 

 0.09 and 0.14. This measurement refers to the fin upon the colored side. 

 Its shape is also variable; it is sometimes pointed, sometimes obtuse, 

 owing to difference in comparative length of the upper rays. It is 

 usually black, with a narrow whitish tip. The number of rays varies 

 from 9 to 14. 



(6) Length of ventrals. — This is also extremely variable on both sides. 

 The range on the blind side is 0.0475 to 0.07, and on the eyed side 0.056 

 to 0.0775. The difference between the length of the two fins upon the 

 same individual varies from 0.0025 to 0.0155. 



(7) Contour of lateral line. — In some individuals this is essentially 

 straight, in others considerably arcuated above the pectoral. This 

 appears to be an individual variation. The two European specimens 

 show a perceptible difference in this respect. In his diagnosis of Pleu- 

 ronectes cynoglossus, Dr. Gunther states that the lateral line is straight, 

 without curve. 



(8) Position of the eyes. — Dr. Gunther states that in P. elongatus the 

 upper eye is in advance of the lower. This is doubtless quoted from 

 Yarrell. Neither the figure of Yarrell nor that of Couch indicates any 

 such character. 



(9) Scales in lateral line. — The number cn the blind side ranges from 

 109 to 150, on the eye side from 110 to 140, there being no relation be- 

 tween the different sides of the same fish. 



(10) Radial formula. — In the dorsal this ranges from 102 to 120; in 

 the anal, from 87 to 100. There is no apparent relation between the 

 number of rays and the relative proportions of height and length of 

 body. A large number of rays in the dorsal is usually accompanied by 

 a relatively large number in the anal. 



(11) Transverse rotes of scales. — Their number above and below the 

 lateral line is nearly equal. The range is about from 40 to 50. There 

 appears to be no relation of number of transverse rows to comparative 

 height of body. 



The thermal range of the species appears to be defined nearly by the 

 limits 340 ail( i 450 p. 



