260 DEFORMITIES IN SALMONIDAE. 



monstrosities ^). Saudifort ^) raeutious a monstrous salmon- 

 head, but neither figures nor describes it. 



The latest researches of Dareste and Gerlach have more 

 and more fixed the attention on teratological forms , and 

 therefore I hope it will not be without interest, when I 

 give here the description and the figures of 2 monstrous 

 Salmonidae, that were presented to the Leyden Museum. 



The first is a specimen of the salmon-trout (»Sa/?no ^r-^^^a) 

 captured in our rivers in the month of October 1884. It 

 is an unripe male of 25 cm. length , in a very wholesome 

 condition , but with a deformity of the head , which is figu- 

 red on pi. 7, fig. 1. 



The prenasal portion of the head is but slightly deve- 

 loped and therefore the normal under-jaw projects in front 

 of the snout. The praemaxillaria are small, and asymme- 

 trically developed , the right one being the largest and 

 bearing 4 teeth , the left one smaller with only 3 teeth. 

 These praemaxillaria are not directed forwards , but curved, 

 and each growing towards its fellow; therefore the head 

 gets a short and broad appearance. The two bones do not 

 meet at the midline but are connected by a cartilagenous 

 strip. This strip is 4 m.m. broad , and shows at the under- 

 side a rounded emargination , giving to the snout some 

 resemblance with a hare-lip. The supra-maxillaria are a little 

 shorter than in the normal state , slightly curved and 

 bearing small teeth, which are directed inwards. 



The second monstrosity is a specimen of Salmo salar , 

 and was presented to the Leyden Museum by Messrs. ten 

 Houten & de Raadt at Kralingsche Veer. The head is 

 figured on pi. 7 , fig. 2 and shows no shortening , but a 

 curvature of the prenasal portion. 



I suppose this deformity is caused by the slight deve- 

 lopment of vomer, parasphenoid and palatines. Because 



1) Museum anatomico-pathologicam Vratislaviense. Vratislaviae, 1841. Tab. 3, 



2) Sandifort, Museum anatomicum. 



Notes from the Leyden Museum , Vol. VII. 



