St. Andrews Marine Laboratory. 191 



mature condition takes place more rapidly than the previous 

 growth. Such is the general impression, though no exact 

 observations have been made. 



The halibut has thus one of the largest and most beautiful 

 of pelagic ova ; but since it has never been obtained in a tow- 

 net, it is possible it may be less buoyant than the smaller 

 eggs. 



No fertilized ova having yet been obtained, the larval and 

 the early postlarval stages are unknown. On the 28th of 

 June, however, on Smith Bank, a well-known fishing-ground 

 in the Moray Firth, a closely allied form, if not this species, 

 was procured in the mid-water net along with young gadoids, 

 gurnards, and pleuronectids. The total length is 9'5 millim. 

 and the greatest depth 3*8 millim. It is distinguished by 

 the thickness of the body (the depth of which, however, is 

 comparatively moderate), by the character of the head, and the 

 presence of branchiae projecting behind the opercula. The 

 thickness and firmness of the body and the condition of the 

 branchiaj would lead to the conclusion that it is not a very 

 young fish, yet the embryonic tail is still present. Before 

 the young turbot reaches that length the condition of its tail 

 is wholly different. 



The head is characterized by its massive appearance. 

 The eyes are lateral and of considerable size. The marginal 

 fin is considerably injured, but it seems to have been of 

 moderate depth, traces of true rays appearing both dorsally 

 and ventrally, and especially in the caudal. The terminal 

 curve of the notochord is pronounced but does not taper much, 

 and the embryonic fin apparently forms a shorter lobe than 

 in the other pleuronectids. The vent is situated a little in 

 advance of the median line of the body, which, as well as the 

 head, is speckled with minute blackish-brown points. Those 

 chromatophores present on the abdomen have undergone 

 considerable change, after immersion in spirit, viz. a spreading 

 out of the marginal pigment, while a black speck is left in 

 the centre. The chromatophores on the lateral region occur 

 with some regularity. Indications of two pigment-touches 

 appear in the marginal fin, viz. over the tip of the pectoral, 

 and another about the centre of the post-abdominal region of 

 the body. Ventrally a single patch is situated between the 

 anus and the hypural region. The pigment invades the fin 

 and thus resembles that in the pleuronectids generally. On 

 viewing the dorsal edge from above, the cephalic and the two 

 marginal touches, which extend on the fin, are best seen. 

 Ventrally a little pigment over the abdominal surface and the 

 patch in the anal fin are noticeable, while chromatophores are 



14* 



