IRISHES IN THE SOUTH-WESTERN DISTRICT. 43 



ventral, in wliich case it is unaccompanied by pigment ; and it may 

 be remarked that minor differences in the position of oil globules do not 

 deserve the attention that has sometimes been bestowed on them. 



Pigment is rather variable, but is never present on the marginal fins 

 nor about the yolk, except along its posterior edge and about the 

 globule. Chroraatophores of both colours (the yellow being golden- 

 brown by transmitted light) are scattered along the head, trunk, and 

 tail of the larva. These are of large size, stellate or dendritic, and 

 arranged for the most part along the dorsal and ventral regions. There 

 may be an approach towards a postanal bar by discontinuity posterior 

 to the rectal region, but this is never well marked. Chromatophores 

 extend some way along the hind wall of the rectum, and, as we have 

 seen, along the hinder profile of the yolk. The skin is markedly 

 papillate, but the margins of the fins are devoid of the digitiform cells 

 noticeable in Arnoglossus or Coris. The notochord is multicolumnar. 



In later stages the larva becomes characterised by the development of 

 a very strongly marked renal band of very large black chromatophores, 

 exteuding from the otocyst to about the anterior third of the tail. A 

 dorsal band, corresponding posteriorly to the first, extends forward 

 about half-way along the abdominal region. A third ventral abdominal 

 band occupies the greater part of the abdominal length, and the 

 chromatophores on the dorsum may form a fourth, extending from the 

 cerebellar region to a little behind the shoulder girdle. Yellow pigment 

 seems to be everywhere associated with the black, but is almost com- 

 pletely masked where the latter exists. It is conspicuous, however, on 

 the sides, especially post-anally, and on the snout, mid-brain, and 

 otocystic region. More or fewer black chromatophores are present 

 about the head in the regions named, and also on the lower jaw and 

 isthmus. The fins are absolutely devoid of pigment, except where 

 a little extends post-anally from each margin of the tail. There is 

 no pigment at all about the posterior two-thirds of the tail of the 

 larva. 



At this stage, the most advanced reached by my artificially fertilized 

 ova, as also by tow-net specimens, the larva measures 2"98 mm., of 

 which 1"55 is anterior to the anus, and 1'97 is pigmented. The yolk is 

 only represented by the remains of the oil-globule. The liver and gut 

 are well developed, the latter still without convolution. The mid-brain 

 is elevated, and there is a distinct approach to the rostral prominence of 

 the adult. The trunk is only of moderate depth, but the posterior half 

 of the tail tapers rather suddenly. The marginal fins are only of 

 moderate width, the dorsal having its origin behind the mid-brain. The 

 epidermis remains markedly papillate, but the outline of the fin-ridge is 

 unbroken, save at the caudal extremity, where it is somewhat pectinate, 



