70 PEOF. C. STEWART ON A HEEMAPHRODITE MACKEREL. 



The right genital gland, 47 millim. in length, appeared to be of 

 entirely ovarian nature, and contained many large ova which pro- 

 truded from its surface. The posterior extremity of the gland Avas 

 ruptured, but whether before death or from subsequent baudling 

 I am unable to say. 



The rigbt duct, 73 millim. long, is a delicate tube attached to 

 the ventral wall of the swimming-bladder, and extending from 

 the posterior end of the gland to its termination in the uro- 

 genital chamber ; there were three ova lodged in the duct at the 

 latter point ; and a short distance in front the duct was ruptured. 



The left genital gland is 59 millim. in length. At 26 millim. 

 from its anterior extremity the ovarian structure is replaced by 

 testicular, this testis region being 16 millim. long and 5 millim 

 broad ; it is abruptly defined by a constriction from the ovarian 

 region in front, but posteriorly expands into the second portion 

 of the ovary. The form of the testis is roughly that of a three- 

 sided prism with a shallow groove in the middle of its ventral 

 face. 



The left duct is similar to the right, but is unruptured ; they 

 open side by side in the anterior wall of the uro-genital chamber. 



There are two special points of interest in this case. Firstly, 

 that from self-fertilized eggs healthy and normal young were 

 reared ; secondly, that this fish was fundamentally a male (as 

 evidenced by the possession of genital ducts), the greater part of 

 whose genital glands had acquired an ovarian structure. It is 

 also, so far as I am aware, the first iu stance recorded of the 

 occurrence of hermaphroditism amongst the Salmonidse. 



On a Hermaphrodite Mackerel, Scomber Scomher. 

 By Prof. Charles Stewart, Pres. Linn. Soc. 



[Eead 4th June, 1891.] 



(Plate III.) 



Mr. "W. B. Tegetmeier has recently presented to the Museum 

 of the E,oyal College of Surgeons a hermaphrodite Mackerel ; 

 and as there are very few cases on record, and this specimen has 

 some unusual features, I have thought it desirable to give a brief 

 account of it. The fish was 400 millim. long, and was received by 



