TlIiBOT AND liltll.L. 



433 



— tlioii^Ii, accordiiio- to Stoueh, it attains a length of 

 from 12 to 1<S dm. — as to i-cmiiul us very strongly 

 of tlie Megrim. The two othi'rs, however, are among 

 our better Flatfishes — one of them aniono: the best and 

 fattest. They are also charaeterized by the exception- 

 ally deep (shoi-t) form of the bodv, \\lii( li is relatively 

 shorti'i- than in any of tlie other flatfishes. The mouth 

 is turned up sharply. The eyes are well separated, 

 most so among the Scandinavian forms of the sub- 

 family, though not nearly so fiir apart as in some 

 members of the preceding genus. 



Few as are the species of this genus, their rela- 

 tions to each other, especialh- in the case of the two 

 that belong to the European fauna, are in the highest 

 degree interesting. Not only is their geographical range 

 so extensive as to admit of the form's being influenced 

 by very dissimilar environments"; but in addition to 

 this a large number of intermediate forms are known, 

 which can obviously be explained only on the assump- 

 tion that they are hybrids''. ^Ialm has described one 

 of tliese forms under the name of nhonihus hijhridus. 

 Both his specimens Avere females, and most closely 

 resembled Bofhus maximus. The Royal Museum has 

 received from StrQmstad, through Mr. ('. A. Hanssox, 

 two males, one of which is more like ISothtis rliomhiis. 

 Thus it is very difficult to find fixed, constant charac- 

 ters for the two species — for many different combina- 

 tions \\v,\\ probably be found. However, the forms 

 known in Scandinavia may be distinguished as follows: 



I: Xuinbcr of rays in the anal liii 

 lit most 50. J.fust flcpth of tlic 

 tail less than 20 % of the greatest 

 depth of till' hofly. Abdominal 

 curve of the lateral line higli and 

 short, its heiglit being about half 

 its lengtli, wliieli is about •' 4 of 

 the lentrtli of the middle caudal 

 rays. 

 .'1: Length of the head behind 



the lower eye more tiian 1 7 %. 



and of the left maxillary bone 



more tlian 12 ?i, of the length 



of the body Bothus maximus. 



JJ: Postorbital length of the head 



less than 17 K, and of the 



left maxillary bone less than 



12 %, of the length of tiic 



body Bothiis maximus hybridus. 



W: Number of rays in the anal iin 

 more than 50. Least depth of the 

 tail more than 20 % of the great- 

 est depth of the body. Abdominal 

 curve of the lateral line low and 

 long, its height being about '/j 

 of its lentrth, which is about 

 equal to that of the middle cau- 

 dal rays. 



A: Postorbital length of the head 

 more than 16 K, and the great- 

 est depth of the body more 

 than 50 %, of the length of 



the bodv Botlius ritombui hybridus. 



B: Postorl'ital length of the head 

 less than Iti '., and the great- 

 est depth of the body less 

 than 50 %. of the length of 

 the body Botlius rhombus. 



" If we coniijare, for example, Canestkini's descriptions of Bothus majcimus and Bothus rhomhus from the Mediterranean with speci- 

 mens of tliese species from Scandinavian waters, we find tl.at, tlioiigli the differences are parallel — the former having a larger head, fewer 

 rays in the dorsal and anal fins etc. — still the bonndaries between the species are entirely different in the Mediterranean and in our fauna. 



'' We are still without the necessary experimental evidence to show that this is the case; and that this is the only operating influence 

 is scarcely probable, for these intermediate forms occur in localities, in the Baltic for example, where only one of these species is found in 

 its typical form. 



Scandinavian Fishes, 



