OBSERVED AT PLYMOUTH IN THE SPRING OF 1902. 601 



not resemble those hatched from the other series of eggs, though it seemed 

 to me that they might have been very well represented by the figures of 

 either of Holt's Species x. or xi. {lor. cit., PI. IL, Figs. 19-21, PI. VIIL, 

 Fig. 64), according as the light through the microscope was manipulated. 



The eggs with the larger oil globule appeared in the tow-nets nearly 

 a fortnight earlier than those with the smaller, the actual dates of 

 their first occurrence being March 3rd for the former and March 15th 

 for the latter. However, on March 7th a female Zevgopterus norvegicus 

 was dredged up from which eggs were obtained by slight pressure. 

 These eggs appeared to be ripe, and floated in the sea-water, and were 

 quite translucent. Those measured varied between "85 and 90 mm. 

 and the oil globule between '13 and '14 mm. 



My facts are perhaps too few to permit a definite conclusion, but at 

 least they suggest that the eggs with the smaller oil globule (Mr. Holt's 

 Species xii.) are distinct from those with the larger globule (Mr. Holt's 

 Species x. and xi.), and that the former eggs belong to the smallest 

 topknot, Z. norvegicus. 



Gadus. 



The descriptions given by the various authors of the eggs of the 

 different species of the genus are up to the present insufficient for 

 separating those of several of the commoner kinds, such as G. luscus, 

 minutus. axi^ pollachhis. and possibly also some of those of G. merlangus. 



In the first place certain eggs varying in diameter between 1"2 and 

 1-28 mm. seemed to separate out clearly as those of 6. merlangus. 

 Yellow pigment became early visible in the developing embryo, and 

 the larvae when hatched showed conspicuous yellow chromatophores all 

 over the head, body, yolk sac, and dorsal and ventral fins. These eggs 

 I have referred to in the record as those of G. merlangus. Twenty-two 

 larvae from these eggs were measured within thirty-six hours of hatch- 

 ing, and their length varied between 3*24 and 3'98 mm., the commonest 

 length being about 3 '6 5 mm. 



About 115 other Gadus eggs were obtained, those measured varying 

 in size between "90 and 119 mm., as follows : — 



Size ill millimetres. "90 93 "94 '95 "96 -97 '98 "99 I'O l-Ql 1-02 I'OS 105 1-06 



Number of eggs. .13261793 14 2 4 2 1 1 



Size in millimetres. r07 I'OS r09 I'l I'll 1-12 1-13 VU V\G VVt 1'18 1-19 12 



Number of eggs. . ^ 2 1 3 1 1 3 1 1 2 2 1 ~2 

 I hatched many of these eggs, the larvae varying as follows : — 



Size in mm. -95 -96 -97 '98 '99 I'O 1-01 1-02 I'OS 1-09 I'l 1-2 



Length of 



larvae 



in 



millimetres. 



3-26 



