The Germ-cells of Lophius. 571 



in the germ-cells themselves. In no case has there been found 

 any conspicuous difference, arising suddenly as in the case of a 

 few well known species of invertebrates. 



II. Observations on Lophius piscatorius L. 

 1. Material and Methods 



The fish which is the subject of this study belongs to the order 

 Pediculati (the anglers), and is known locally by a number of 

 names such as 'fishing frog,' 'goose fish,' etc. It is common in 

 the shallow waters of the North Atlantic on both American and 

 European sides, ranging as far south as Cape Hatteras and the 

 Mediterranean. The eggs from a single female, estimated to ^ 

 number from forty to fifty thousand, float near the surface of the i 

 water, inclosed in a ribbon-shaped gelatinous mass a foot wide and 

 30 or 40 feet long.- 



Alexander Agassiz describes the egg mass as an enormous rib- 

 bon from 2 to 3 feet broad and 25 to 30 feet long.^* His figures 

 and account of the newly hatched fish agree well with the material 

 used in this study. He figures the eggs but gives no record of 

 their size and I have had no opportunity to measure living ones ; 

 but from eggs in a good state of preservation they appear to meas- 

 ure about 1.7 mm. in diameter. 



The greater part of the material used in this study was from the 

 coast of Maine, collected and preserved by the Harpswell Lab- 

 oratory of Tufts College. A series of fourteen vials of embryos 

 of successive stages were studied. In the following account 

 these stages are referred to by the consecutive numbers 1-14. 

 In stage 1 cleavage has advanced to a point at which the germ- 

 disc in several cells in thickness, but has not yet begun to grow 

 around the egg. Owing to the spawning habits of Lophius, it is 

 only by chance that the early cleavage stages are collected, the 

 segmentation always being somewhat advanced when the eggs 



2 Jordan, David Starr, 1905. A Guide to the Study of Fishes. 

 * Agassiz, Alexander, 1882. On the Young Stages of Osseous Fishes, Part 3. 

 Proc. Amer. Acad. Arts andScis., 17. 



