Dublin Natural History Society. 3927 



Islands, it has abundantly multiplied, proving, where climate and temperature are 

 adapted, how readily the propagation can be extended." 



The author here read a letter from Mr. Daniel Smith to Mr. S. Gurney, jun., in 

 reference to the impregnated ova of salmon and trout sent from England to Australia. 

 This letter is given in our number for J une, 1852, (Zool. 3504). He then continued: — 



" Mr. Gurney also wrote to me from Carshalton on the 21st of January last, this 

 pleasing communication : — * I expect to begin spawning my fish tomorrow. I have 

 just heard that some spawn I sent to New Zealand about two years ago, was hatched 

 in due course, and that the fish from my river (the Wandle), are now flourishing in 

 the Antipodes.' This is the course to make Natural History truly useful ; and is it 

 not of the highest importance to have it so directed, that a knowledge of the habits 

 and spawning states of our most esteemed fish can render their distribution to unpro- 

 ductive waters, where climate and temperature may prove congenial. The object of 

 the present paper is not to enter fully into the physiological details of fcetation, or the 

 development of the embryo, to the growth or development of extrication from the ovum, 

 but merely the record of observations made during a recent visit to Mr. Gurney, at 

 Carshalton." 



After a brief description of Mr. Gurney's grounds, the author proceeds : — 



" I was fortunate in visiting Carshalton about the middle of last month, and had 

 the opportunity of learning from Mr. Gurney, and of seeing, his successful plans. At 

 that time the spawning-season was over, and the parent fish had retired from the de- 

 posit-beds to deep water. After the artificial impregnation of the ova, they are placed 

 in beds of gravel, in boxes secured with wire gratings, and through which a stream ot 

 water plays, of sufficient depth to allow the light and temperature necessary for the due 

 development of the embryo fish. In such state the ova are prepared for transportation 

 to our remotest colonies. Mr. Gurney had at the time some ova kept in the house in 

 a tin vessel, which were spawned at Christmas, and sent to him from Derbyshire. Se- 

 veral had extricated themselves from the eggs, and were actively moving through the 

 water, with the large vitelline sac attached. The time of extrication much varies, ac- 

 cording to season or temperature, generally from six to seven weeks. These, under the 

 microscope, afford most beautiful examples of the circulating system, and I was fortu- 

 nate in witnessing the extrication of one from the ovum. When the ovum is fully ma- 

 tured, the external tunic or shell becomes exceedingly thin and transparent, is easily 

 ruptured, and the tail of the embryo fish unbending, first forces the passage out. At 

 this time the eyes are large and prominent, and all the fins are rudimentary and unde- 

 veloped. The little creature, however, rapidly grows, the irides assume a brilliant 

 tinge, the pectoral fins rapidly play, and traces of the formation of the dorsal, caudal 

 and anal fins are seen. It is then that its extreme beauty is so conspicuous under the 

 microscope. The vitellicle is attached to the forepart of the abdomen, of an oblong 

 shape, highly vascular, and the vitelline vessels and circulating cells are beautifully 

 shown ; the blood flows through the blood-vessels ramified along the sides of the back, 

 rushes through the large vessel of the vitellicle, and communicates with the heart, 

 which is situated under the throat, immediately anterior to the pectoral fins, the richly 

 coloured blood in the pulsating tube beating from 60 to 70 in a minute. Along with 

 the blood, a transparent matter is seen in constant circulation. This state was admi- 

 rably shown to me by Mr. Gurney, who kindly presented me with four specimens, and 

 these lived for three weeks, until killed within these few days, probably by some impu- 

 rity of the water. At the time of their death they had grown much, were exceedingly 



