FISHERY BOARD FOR SCOTLAND. 



ON DISEASES AND ABNORMALITIES IN FISHES 

 OF THE COD {GADUS), FLAT-FISH (PLEURO- 

 NECTES), SALMON (SALMO), SKATE (RAIA), 

 etc., FAMILIES. 



BY 



H. CHAS. WILLIAMSON, M.A., D.Sc, F.R.S.E., 

 Marine Laboratory, Aberdeen. 



(Plates I. -VIII.) 



CONTENTS. 



Dohus achis, n. sp. — An Intracapillary Parasite of the Haddock (Gadits 

 leglefinus), 



s calico 



ias), 



Muscles of the 



Catfish 



Roles trelis, n. sp. — A Parasite of the Cod (Gadi 



Columnar Disease in the Cod, 



Diseased Li\ T er of Cod, 



Diseased Kidney of Tusk (Brosmius brosme), Cod, and Saithe (Gadus 



virens), .... 



Cancerous Tissues in Fishes, 

 Lymphostasis in the Saithe, 

 Pleistophora hippoglossoides, Bosanquet, in the 



(Anairhichas lupus) and Zoarces viviparus, 

 Tumours in Fishes, 



Ulcer on Plaice (Pleuronectes platessa), . 

 Pimpled Skin of Cod, &c, 

 Pinkish Flesh of Cod ; Disease of the Eye, 

 Perforation of the Gut, 

 Discoloured Flesh of Salmon, 

 Worm Parasites of Fishes, 



Humpty Cod, Haddock, and Hake (Merhiccius vulgaris), 

 Spinal Curvature in Cod, Haddock, and Horse Mackerel (Caranx 



trachxirus), ........ 



Page. 



4 



7 

 8 

 9 



12 

 14 

 14 



16 

 18 

 22 

 25 

 25 

 25 

 27 

 30 

 31 



34 



Diseases and abnormalities are common in fishes. They are in 

 many cases due to parasites. I have from time to time received a 

 considerable number of abnormal specimens, and for these I have 

 been indebted, in large measure, to the courtesy of Mr. W. S. Eunson 

 and Mr. B. Erlandson, Aberdeen. 



In the following pages I describe a number of diseased conditions. 

 They include instances of tumours, parasites located in the muscles, 

 kidney, and liver, deformities of the vertebral column, etc. 

 500— Wt. 17124/213 (15). 



