2o6 BULLETIN OF THE BUREAU OF FISHERIES. 



time, in stripping a fish this fact should be borne in mind, and no forcible attempt 

 should be made to express more than those eggs which easily flow under gentle pressure. 

 It may take several operations to secure all of the eggs, and as the eggs begin to ripen 

 in the posterior part of the ovary, to obtain them it is not necessary to squeeze the 

 whole length of the abdomen. In fact, it is liable to injure the eggs or rupture the 

 ovarian membrane to do so. Experiments indicated that by the usual method of strip- 

 ping a large percentage of the eggs are obtained in the first operation. The question, 

 therefore, arises whether the number of good eggs obtained would be reduced by a 

 gentler operation and whether a second operation is necessary. In any event it would 

 seem to be a more rational procedure to follow nature and first remove the eggs in the 

 posterior end of the fish, using no more force than gentle pressure near the vent, with a 

 movement toward it. If eggs do not flow at first, repeated, short, gentle strokes may 

 cause them to, if they are ready to be deposited. Some egg takers hold the fish belly 

 up at an angle which will permit the eggs to fall into the pan for receiving the eggs. 

 It would seem to be more in accordance with nature if the fish were held belly down 

 thus permitting the eggs to flow or roll along the oviduct toward the vent, as others 

 are emitted. The flow may be aided by gentle stripping motions repeated each time a 

 little further forward, not going further than the region of the middle of the ventral 

 fins. When the eggs cease to flow under gentle stripping pressure the operation should 

 cease. Possibly not as many eggs would be obtained by this method as by the usual 

 forceful method, but by operating only once or twice with due care, the danger of both 

 external and internal injuries is lessened, and the breeder is saved, providing retained 

 eggs are not harmful. This latter point remains to be ascertained. 



LIST OF WORKS CONSULTED. 

 Atkins, Charles G. 



1900. The Atlantic and landlocked salmons. Iti A manual of fish-culture, revised edition, pp. 

 17-60. Washington. 

 Balfour, Francis M. 



1878. On the structure and development of the vertebrate ovary. Quarterly Journal of Micro- 

 scopical Science, new series, vol. 18, pp. 383-438, Pis. XVII-XIX. London. 

 1881. A treatise on comparative embryology. Vol. II, 677 pp., illus. London. 

 Beard, J. 



1890. The inter-relationships of the Ichthyopsida: A contribution to the morphology of verte- 

 brates. Anatomischer Anzeiger, Bd. 5, pp. 146-159 and 179-188. Bardeleben: Jena. 



Boulenger, G. A. 



1904. Teleostei (systematic part). In The Cambridge natural history, vol. 7, pp. S39~727. Mac- 

 Millan & Co. New York, London. 



Bridge, T. W. 



1904. Fishes, exclusive of the systematic account of Teleostei. In The Cambridge natural history, 

 vol. 7, pp. 139-537. MacMillan & Co. New York, London. 

 Day, Francis. 



1887. British and Irish Salmonidae. , 298 pp., illus., 12 pis. London. 



Felix, W. 



1895. tjber die Entwickelung des Excretionssystems der Forelle (Vomiere, Umiere, Nachniere). 



Verhandlungen der anatomischen Gesellschaf t , 9 vers, pp. 147-152. Basel. 

 1897. BeitiSge zur Entwickelungsgeschichte der Salmoniden. Anatomische Hefte, Abth. i, Bd. 

 8, pp. 249-466, 8 pis., and 39 figs. Wiesbaden. 



