62 ADDITIONAL MINOR ABNORMALITIES 



Gonads. "Williamson (270 p. 64) describes a partly hardened tough tuberculated ovary in the 

 haddock, and Hefford (91) notes arrest of development in one gonad of a male conger. 



Hernia, Mudge (166) describes an adult female dogfish with hernia of part of the stomach and 

 certain other organs into the lumen of the pharynx. 



Kidney. Howes (100) gives an account of variations in the kidney of Raia clavata which point in 

 his opinion to a process of adaptative evolutionary change. 



Lateral line. Supplementary in Aeipenser (Jaquet 110). 



Bo. Interrupted in a haddock (Mr. J. Ritchie, in a note to the author). 



Mouth. Several instances have been put on record of fair-sized fish in which tbe mouth opening 

 was either absent or minute, the condition being associated with other cranio-facial 

 defects. Cases of the kind are noted by Laurence (136a) in Sclerognathus, and by 

 Hofer (96a), St. Hilaire (213 I. p. 285), and Steindachner (234a) in Cyprinus. Freund 

 (70 p. 719) also cites records from Cyprinus by Schiemenz and Bruyant. 



The bones of the upper and lower jaw exhibit various degrees of defect or malfor- 

 mation, the actual closure or narrowing of the mouth being effected by skin or membrane 

 extending over their representatives. Food must have entered the pharynx through the 

 gill slits with the respiratory current. 



It will be remembered that the specimen described by Donnadieu (see p. 51 of this 

 work) had an extremely small mouth opening, and that a similar condition (p. 42) was 

 found in one of my cyclopic trout embryos. 



No doubt in its best marked forms the condition is a congenital one, although 

 healing after wounds certainly accounts for many minor cranio-facial defects. A number 

 of instances of this kind have been brought together by Hofer (96a) and Freund (70), 

 while Garstang (75) notes a remarkable malformation in the mouth of the sea-bream, 

 which he thinks was probably the result of injury. 



Muscle. An abnormal superior oblique in Carcharias (Allis 3). 



Nerves. Variations in the pelvic plexus of Acanthias (Punnet 196). 



Notched body. Johnstone (116) describes a plaice with a large notch on the ventral edge of the 

 posterior part of the body, and thinks that injury was the probable cause. 



Ovaries. Three in a sturgeon (Grimm 83). See also under Gonads. 



Oviduct. Present in an adult male skate (Matthews 151). See also Borcea (27). 



Pyloric caeca. Branching in Centrolophns (Eiggio 204). 



Respiratory organs. Variations in the lamprey and hag (Howes 102). 



Reversal (Metastrophy, Cunningham, 50) seems to occur with varying frequency in all, or 

 practically all, the species of flatfish. In this condition the side which is normally the 

 under or blind side lies uppermost, and there is a corresponding interchange between 

 the two sides as regards their external features and their ocular and cranio-facial 

 characteristics. The viscera, however, retain their usual disposition. Thus alike in 

 normal and in reversed flatfish the liver hangs down to the left side of the abdominal 

 cavity and the coils of intestine are directed to the right (Cunningham, 50a p. 861). 



Scales. Increased number on one side in the pilchard (Bateson 15-16 and Lowne 146 p. 119). 



Snout. Bifid tip of snout in Aeipenser ruthenus (Jaquet, quoted in Freund 70 p. 719). 



Spiral valve of Raia. Exhibiting a lai-ge degree of variation (Parker 183a). 



Teeth. Male Raia with blunted teeth (Day 54 II. p. 344). 



Acanthias with gills instead of teeth in the upper jaw (Grosser 85). 

 Rhino2)tera, with abnormal dentition (Woodward 273). 



Telescope eyes of goldfish (Tornier 249, and others, see above under fins). 



