Morrhua punctata and Morrhua vulgaris. 369 



The arch is also expanded laterally, arising from the pres- 

 sure of one vertebra upon its neighbour, while the transverse 

 processes are stronger, longer, and generally nodulated, present- 

 ing much the appearance of broken bones badly united. These 

 diseased portions are neither uniform in extent nor in situation. 

 In some examples only a few vertebrse are involved, in others 

 the greater part of the spine is affected; again, we find the 

 thickened part near the tail in some, while in others it is nearer 

 the head. Occasionally two diseased portions are met with in the 

 same fish, having a few healthy ^vertebra? intervening. If the 

 diseased portion is near the head, the extent of disease is greater 

 than when nearer the tail, and has a greater effect in the pro- 

 duction of the deformed external appearance of the fish. 



It is difficult to account for this disease of the spine. I can- 

 not myself arrive at any conclusion upon the subject. It may 

 be congenital. The fishermen believe it arises from accident ; 

 if so, the cause must be constantly in operation, as there is no 

 season that I have not met with examples — I admit, however, 

 oftener in some years than in others. It is far more common 

 m the Haddock than in the Cod ; and the fishers assert that 

 th% occasionally meet with it in the Coal-fish, the Merlangus 

 carbonarius ; but I have not myself seen it in that species. 



I have never seen it in any large full-grown Cod, but often in 

 Haddocks 18 or 20 inches long, which perhaps might strengthen 

 the argument that it is congenital. 



^ There is no difference in the flesh ; it eats equally well, and 

 IS never rejected in the market. 



If I might speculate, I would suggest as a cause one which, 

 imder similar circumstances, produces deformity in the human 

 bones, — viz. debility in the vascular system, in consequence of 

 which the bones lose their phosphate of lime, become soft and 

 spongy, then absorbed, and the joints, as in the vertebra before 

 us, become thickened and enlarged— in short, rickety, as we 

 find in the human subject. 



EXPLANATION OF THE PLATES. 

 Plate XV. 



Fig. 1. The healthy spine of the Haddock. 



Fig. 2. The spine of the Haddock deformed nearly throughout its whole 



length. 

 Fig. 3, Another example of deformed spine in the Haddock, confined to 



the caudal extremity of the fish. 



Plate XVI a. 



Figs. 1 & 2. Two examples of the spines of {Morrhua punctata) deformed 

 Cod. The vertebrae much compressed and thickened. 



Ann, k^ Mag. N, Hist. Ser. 3. Vol.y, 25 



