Report on Diseases and Abnormalities in Fishes. 35 



my notice. Storrow records it in a codling 9| inches (25 cm.) in 

 length . 



The deformity does not appear to affect the general health of the 

 fish, for in three cod, a male and two females, measuring 76-90 cm., the 

 reproductive organs were ripening normally. The body of the fish is 

 malformed externally (fig. 162). In this drawing the tail is shown 

 in a horizontal position, but it could be kept vertical. The trunk 

 shows bends to the right and left : it is bilaterally asymmetrical. 

 The fish, however, tends to keep a general straightness, as is seen 

 by the run of the unpaired fins. The abdominal cavity in the fish 

 (fig. 162) showed a bend to the left and then to the right. The 

 swim-bladder followed the curves. The vertebral column shows a 

 much greater distortion than the trunk. Fig. 168 represents the 

 line taken by the vertebrae of one of the fishes, seen from above, 

 while in fig. 167 a side view of the same is given. 



Part of the vertebral column of one fish (fig. 162) appears in 

 dorsal view (fig. 159). At the part near the first hsemal arch (In) 

 the vertebras were lying nearly on their sides. The column began 

 to bend to the right at the 11th vertebra. The 12th went to the 

 right. The 13th to 17th turned to the left. The 18th vertebra 

 began the return to the right. Vertebra 19 to 23 went to the right. 

 Vertebra No. 24 was normal. The total number of vertebrae was 

 52. The neural spines have been broken or stronglj* bent : some 

 of them show swellings which indicate repaired fractures. 



In the bent portion the vertebras are asymmetrical (cp. fig. 166). 



A drawing of part of the vertebral column of another deformed 

 cod is given in fig. 163. The neural spines have been much 

 injured ; they have oeen repaired in various ways. The neural 

 arches of vertebras 16 and 17 have been broken on the left side only. 

 The hasmal arches of vertebras 19, 22, and 24 were broken on the 

 right side only. This would indicate a torsion of the fish. 



A third large cod showed a similar deformity. In addition to 

 the fracture and bending of the spines and arches, one vertebra (No. 

 29) was broken right across (fig. 171). The neural and hsemal 

 arches were also fractured. The injury had not been repaired : the 

 fracture remained as a movable joint. In this fish there was an 

 indication in some of the joints of disease similar to what occurs in 

 the humpty cod. 



A well-marked case of spinal curvature in the haddock is preserved 

 in the Laboratory. A horse-mackerel (Garanx trachurus) also 

 exhibited a like deformit} r . 



Is the curvature the cause of the fracture of the spines and 

 vertebra ; or were the injuries to the backbone the result of external 

 violence to the fish ? 



Spinal curvature may occur in larvas, as Day pointed out in 

 reference to salmon. Fig. 165 shows a sea trout (Salmo trutta) 

 which was hatched at the Laboratory, and which showed two curves 

 (b. and M.) in the notochord. 



It is quite possible that in the cod the deformity had occurred in 

 a very young stage, and the curvature had probably so distributed 

 the stresses when the fish was swimming actively as to cause the 

 fracture of the vertebral spines. The vertebral spines are bent so 

 as to bring their tips, which support the fins, approximately into 

 the straight line of the normal parts of the fish. 



