THE COD FAMILY. 295 



The Three-bearded Eockling. {Onos tricirratus, Brtinn.) 



Dr Eaflfaele gives a description of the development of a 

 rockling from the egg, which he identifies with this species. 

 He has examined the mature three-bearded form and finds the 

 same phenomenon of simultaneous maturation of a great number 

 of eggs as we noted in the five-bearded form. He states that 

 the freshly extruded eggs have no colour in the oil-globule and 

 that in many cases there are three or four globules which later 

 unite into one. The egg captured in the surface-water of the 

 Gulf of Naples corresponds with this in all features except that 

 the colour of the oil-globule is yellow, ' like olive oil.' The 

 egg occurs in abundance from November to January and is 

 •74 mm. in diameter, the oil-globule being "218 mm. The egg 

 of the five-bearded form (see above) is closely similar in size, 

 but its oil-globule is considerably smaller ; in fact, according to 

 Raffaele's figures, that of the three-bearded species must be very 

 large in comparison with the egg itself. 



The black pigment makes its appearance early and is 

 disposed regularly in a dorsal double row of round cells, two in 

 each segment. On the fourth day, the pigment is principally 

 confined to the dorsal part of the body-cavity and to two dorsal 

 and ventral masses in the tail-region, a distribution not unlike 

 that of its five-bearded ally. The embryonic fin shows no 

 pigment, and the anus terminates half way to its edge. 

 Further increase in the black pigment is observed in later 

 stages. It will be noticed that although this description 

 resembles that of the five-bearded larva yet the oil-globule 

 of the latter is less than half the size, and the spawning-periods 

 of the two differ considerably. 



Mr Williamson procured one of 45 mm. in length at 

 Magnavacca on the 21st February, so that the growth of this 

 form would seem to approach that of the other species. At 

 this stage the dorsum is dark bluish-black and the sides silvery, 

 while the second dorsal, the anal and the caudal fins show 

 traces of minute specks. The head is somewhat like that of 

 the five-bearded form, but is readily distinguished by the 



