of the Fishery Hoard for Scotland. 



361 



One of these remarkable forms is Br achy pleura, which includes several 

 species from the Indo-Pacific Ocean and from New Zealand. This was 

 placed by Gunther (20, p. 556) in the Turbot-group, on account of its 

 having a " nearly symmetrical mouth " and because " the dorsal fin 

 commences before the eye." A further character may be added to 

 complete its resemblance to the Turbots, namely that the ventral fins are 

 unsym metrical. But here the resemblance ceases, and Brachypleura has 

 even less affinity to the Turbot-group than the Solei-pleuronectinse had. 

 The ventral tins though unsymmetrical are only slightly so, and are 

 similar in structure and position to those of the Hippoglosso-bothinse. 

 Further, as in Citharus, Platophrys, and the Soleidse, some of the 

 abdominal vertebrae bear hoemapophyses. As with the Solei- 

 pleuronectinse, these last two characters are considered to show affinities 

 with the Soleida?. On the other hand, the structure of the mouth is 

 hippoglossoid, the eyes are on the right side, and the olfactory organ, 

 though little developed apparently, is of the same type as in the Plaice- 

 and Halibut -groups. 



Brachyplewa has therefore very close affinities to the preceding sub- 

 family, Solei-pleuronectinse, and differs from it chiefly in the form of the 

 mouth. In order to mark this affinity, and at the same time display 

 the difference, it might be advisable —in the event of further related 

 species coming to hand — to raise this genus to the rank of a sub -family 

 and call it Solei-Hippoglossime. 



Another genus whose position is uncertain is Samaris. This resembles 

 Brachypleura in many of its characters, but in its general form as well 

 as the position of the ventral fins shows a greater resemblance to the 

 Turbot-group. The eyes are, however, on the right side. The structure 

 of the olfactory organ is not yet known. Jordan (32, p. 229) has 

 included with this several other genera, Lophonectes, Poecilopsetta, 

 Nematops, and formed them into a distinct sub-family which he calls 

 Samarinse. Future research may show, however, that the two latter 

 should be grouped with the Solei-pleuronectinae. According to Jordan this 

 sub-family lies between the Plaice and Turbot-groups, but one result 

 of the present investigation is to show that these two groups have been 

 and are in no way related to one another. They are both specialisations 

 from the main stock in different directions, and an intermediate group 

 is unlikely — unless it arose through hybridism. The above genera may 

 be transitional stages from the Halibut-or Turbot-groups to the Sole- 

 group or vice versa, or they may be highly specialised members of the 

 Plaice -group. 



Another genus of uncertain position is the Lepidopsetta of Gunther 

 (22), (Mancopsetta of Jordan). This comes from the southern end of 

 South America, and seems to display affinities both lo the Soles and 

 Turbots* 



* Through the kindness of Prof. D'Arcy W. Thompson, C.B., of the University College, 

 Dundee, and of his assistant, Dr. W. T. Caiman, I have been able to examine some 

 additional forms, and had access to additional literature, since the above pages were 

 written. From these observations it seems very probable that the Deep Sea forms of the 

 Indian Ocean described by Alcock (1, 2, 3), connect the flat-fish fauna of the temperate 

 regions of the northern hemisphere with that of the similar regions in the southern 

 hemisphere. Of these forms Boopnetta (Pcecilopsetta) seems to be one of the Plaice-group, 

 whilst Lceops is of the Turbot-group. In the deep sea forms, therefore (Chascanopsetta is 

 another), we may perhaps have the transitions from the Plaice- and Turbot-groups of the 

 northern hemisphere to the Solei-pleuronectina? of the southern. It would be of interest 

 to know whether the forms mentioned had the Plaice or Turbot type of olfactory organ. 

 In this connection, it may be mentioned that a specimen found at University College, 

 which came from New Zealand and seems to be the representative of a hitherto 

 undescribed species, has the external appearance and character of the Turbot group, but 

 the Plaice type of olfactory organ. 



