69 Part III. — Twenty-fourth Annual Report 



The last example had earstones so small as to be greatly out of piopor- 

 tion to the length of the fish when compared with the others in the series. 

 I mention the fact in order that further attention may be drawn to it. 



Fain. OphidiiDjE. 



Genus Ammodytes. 



Ammodytes tobianus, Linn. The Lesser Sand-eel. PI. i. b., figs. 64 

 and 65. 



The earstones of the sand-eels are very small, and their genoral outline 

 is oval, but somewhat narrow and pointed at the posterior end. The 

 earstones represented by fig. 64 were obtained from a fish 7 inches long, 

 and they measured 3 -5mm. by about l'6mm., while those represented by 

 fig. 65 are only about 2* 5mm. by 10mm., and were obtained from a fish 

 125mm. (5 inches) in length. 



Fam. Pleuronectid^e. 



Genus Hippoglossu*. 



Hippoglossus vulgaris, Flem. The Halibut. PI. iii. a., figs. 1-6 and 14. 



The earstones represented by fig. 1 are those of a halibut that weighed 

 179 lbs. (or within 2 lbs. of 13 stone). The fish was captured in 1884, 

 when I obtained the head of it for examination ; the length of the fish 

 was not recorded. The otoliths measure from 17mm. to 18mm. in length by 

 about 11mm. in width, but the two differ slightly in size. Those repre- 

 sented by fig. 14 were removed from a small halibut about 18^ inches 

 long, and these otoliths measure about 8'5mm. in length by about 5mm. 

 in depth. In this example the length of the earstones is only equal to 

 about one fifty-fourth part of the entire length of the fish. The earstones 

 represented by figs. 3 and 4 are from two fishes that are each about 1 If 

 inches in length, and they measure 6mm. by about 3'5mm., while those 

 represented by figs. 4 and 5 are from fishes measuring respectively 260mm. 

 and 220mm. in length. 



In this species, as in most of the Pleuronectidae, the earstones are flat 

 and moderately thin. Those of the large halibut mentioned above have a 

 somewhat irregular outline; on one side the margin is nearly straight, 

 while the margin opposite is somewhat convex, and exhibits in one of the 

 otoliths a distinctly crenulated edge. One end is obliquely truncate, but 

 in the case of one of the stones the other end has a wide shallow notch, 

 while the other otolith is furnished with a hook-like process. The ear- 

 stones of the smaller fishes are ovate, and have a rather more regular 

 outline ; the posterior end is somewhat truncated, but the anterior end is 

 narrow and rounded. 



Genus Drepanopsetta. 



Drepanopsetta platessoides (Fabr.). Long Rough Dab. PI. iii. a., 

 figs. 7-13. 



In this species the earstones of the larger fishes are broadly ovate, the 

 length being only about one-third more than the greatest width. The 

 upper margin is distinctly arched, but the lower is only slightly and irre- 



