ON THE EMBRYOLOGY OF THE TELEOSTS. 187 



The eggs on which we worked were obtained by surface skimming and were usually 

 found in about equal abundance at day and in the evening, and as a rule were rather 

 more abundant when the tide was coining in than when it was running out. One or two 

 evenings however proved an exception to the rule, as once with about half an hour's skim- 

 ming we found over 700 eggs by actual count. This large number however was except- 

 ional, one hundred or one hundred and fifty being near the average. 



The most numerous form of egg and the one on which our observations were principally 

 made was perfectly spherical, about a thirtieth of an inch in diameter, and perfectly transpar- 

 ent. The shell enveloping it (chorion of older authors) was extremely thin and only under 

 high powers showing a double contour. A Tolles one-tenth objective revealed no traces of 

 any structure in it, nor were there visible any pores such as exist in the egg shells of many 

 Teleosts. 1 The various preparations of carmine and haematoxylin as well as the anilines 

 very cpiickly stained the shell, but a prolonged immersion in any staining fluid colored the 

 contents of the egg but very imperfectly and very slightly, thus offering a striking contrast 

 with the eggs of Merlucius which were studied at the same time by Mr. Van Vleck, and 

 which stained easily and well. As our eggs were obtained by skimming and were mature 

 and fertilized, there existed between the shell of the egg and the egg proper a narrow 

 space filled with a transparent fluid in which the yolk floats freely. This space is the 

 breathing chamber of Ransom. The food yolk or deutoplasm comprises the greater por- 

 tion of the egg over one side of which the formative yolk, or protoplasm, is spread as a thin 

 layer. The deutoplasm is perfectly colorless, free from all oil globules or granules of any sort 

 and of nearly the same refractive index as the salt water in which the eggs were kept, render- 

 ing it an operation of some difficulty to pick the eggs out of the water in which they were 

 kept, on account of their being nearly invisible. The protoplasm was in the early stages 

 relatively very small, composing less than a twentieth of the bulk of the egg. Like the 

 deutoplasm it was perfectly free from granules or globules of oil or food-yolk but it was of 

 a very pale straw-color and was more refringent than the deutoplasm. With eggs of such 

 transparence one could easily watch most of the changes going on, even in the interior of 

 the egg, while it was on the stage of the microscope, thus affording in this respect a more 

 favorable object than the egg of the trout which has been the subject of so much investi- 

 gation in Europe. 



Upon the above described egg most of the observations were made which form the basis 

 of this paper. When any other form is used the fact will be stated in the text. 



We greatly regret that we are unable to identify the eggs on which we worked, 2 but all 

 attempts to rear the young fish beyond a few hours after hatching proved futile. We tried 

 keeping them at the ordinary temperature of the room, keeping them in an ice chest, 

 and in breeding boxes, allowing a free circulation of water, or placed in the water from which 

 the young were taken, but in vain. Mr VanVleck had no better success with the young 

 of Merlucius. 



From the numbers of eggs which we found we supposed that they must belong to some 

 abundant shore fish, and the following observations may aid in approximating the species. 

 The flounder (Platessa americana) is, according to a letter to Mr. G. Brown Goode, a win- 



1 Conf. His. '73 pi. ii. Aubcrt '54 pi. vi, fig. 1. eggs, which turned out to be, as suspected, those of the Cunner 



'- During the summer of 1882 I was able to identify the (Ctenolabrus coeruleus.) 



