Oatty Marine Laboratory^ St. Andrews. 247 



are occasionally found in considerabls numbers in August, 

 when the larger examples caught with a hand-net measured 

 about I inch. They adhere to the blades of the tangles and 

 other sea-weeds, and in the mazes of these find that safety 

 (from the ready application of their suckers) which would be 

 denied them in the open sea. They are also common in the 

 neighbouring waters inshore, being carried hither and thitlier 

 on the floating littoral sea-weeds, and thus frequently get 

 into the tow-nets. 



In February and March only ova are obtained. In May 

 the newly hatched larvce are about 6 millim. in length or a 

 little longer. They are tadpole-like, with the remains of 

 yolk, while the marginal fin is continuous dorsally and ven- 

 trally. The caudal has only embryonic rays, and there is a 

 thickening (hypural) beneath the notochord in this region. 

 The short breast-fins show indications of true rays. In 

 Prof. Agassiz's * youngest stage the caudal was already 

 partly separated from tiie dorsal and ventral embryonic tin, 

 and yet the presence of yolk is not mentioned, while the 

 length was only 4 millim. The foregoing, therefore, though 

 larger, was less developed, as, indeed, his figure shows. He 

 fancifully likens the outline to that of the armoured fishes of 

 the Old Red Sandstone — e. g., Goccosteus. By the twelfth 

 day the fish has increased considerably in bulk and measures 

 6"7o millim. in spirit; and besides the disappearance of the 

 yolk and the increase of pigment, the dorsal has now been 

 transformed into two fins, a short crescentic first dorsal over 

 the vent, having six true rays, and a second dorsal with eleven 

 true rays, joined by a portion of the larval fin (which shows 

 no embryonic rays) to the caudal, the upper region of which 

 (the larval tail) has only embryonic rays to the notch f, ten 

 true rays occurring beneath. The anal fin has ten rays and 

 is joined to the caudal by a strip of larval fiu without rays. 

 In the figure of Professor Alex. Agassiz at this stage {e. g. his 

 fig. 3, pi. iv.) the second dorsal shows thirteen rays, the anal 

 fifteen, and no strip without rays intervenes between these 

 fins and the caudal. He likens it at this stage to the young 

 of Batrachus. 



Professor A. Agassiz gives some excellent remarks con- 

 cerning the coloration of these young forms. " In the youngest 

 stages " (with true rays developing in the tail, or about the 

 twelfth or thirteenth day in Britain) " the head, in a line 

 drawn nearly vertically below the base of the anterior dorsal, 

 is of a light chocolate-brown, with a darker brown band 



* Proc. Arner. Ac. Art3 and Sci. vol. xvii. July 1882, p. 286. 

 t The notch is absent in Professor Aga.ssiz'8 iigiire (pi. iv. tig. 1). 



