IN THE SOUni-WESTERN DISTRICT. 149 



are probably, at most, a few clays old, but the organs of the head are 

 well developed, although the large otocyst shows but little internal 

 complication. The yolk appears to have been entirely absorbed ; an 

 air-bladder is present, though not clearly visible on account of the 

 dense black pigmentation of the abdominal roof. In serial transverse 

 sections I failed to find any connection between the bladder and the 

 alimentary canal. The large fan-shaped pectorals extend some way 

 beyond the anus ; they are entirely devoid of pigment. In this 

 respect, therefore, the young iVtherinc offers a marked contrast to the 

 young Bleuny, which it otherwise resembles rather closely. The end 

 of the multicolumnar notochord is not yet upturned, but there is a 

 slight opacity of the sub-uotochordal region, marked by a black 

 chromatophore and by a number of embryonic caudal rays. The 

 marginal fins are of moderate width. The dorsal arises a little behind 

 the level of the anus: both dorsal and anal are constricted in the 

 peduncular region, expanding again to form the spatulate caudal. 

 The notochord is multicolumnar. The brain-tissues are of a bright 

 yellow colour, not apparently due to pigment. Very large black 

 chromatophores occur in the pia mater of the mid-brain in variable 

 number. The roof of the peritoneal cavity is densely coated with 

 black, intermingled with yellow pigment. Elongated black chromato- 

 phores occur at intervals along the lateral line. Black chromatophores 

 occur variably along the dorsal and ventral margin of the post-anal 

 region. The marginal fins are devoid of pigment. 



In the specimens of 11"5 mm. the trunk is deeper, the snout longer 

 and more pointed. The abdomen is, proportionally as well as actually, 

 somewhat elongated. The gills have become pectinate. The noto- 

 chord shows signs of segmentation, and its extremity is upturned 

 by the development of a tri-lobed hypural mass. Embryonic fin-rays 

 mark the sites of the second dorsal and anal fins. The axis of the 

 pectoral is obliquely rotated. Pigment changes are chielly confined 

 to a backward extension of the dorsal cephalic chromatophores. 



I did not again meet with the young sand smelt until the 14th July, 

 1897, when I caught several at low water in Ealmouth Harbour, above 

 St. Mawes. They were swimming in a small shoal near the surface 

 at the point of a projecting rock, a habit I have noticed in similar 

 stages of the Mediterranean A. Boycri. The specimens caught were 

 of various sizes. Apart from the fact that A. 'presbyter is practically 

 the only British Atherine, the larger specimens can readily be identified 

 with that species by the fin-ray formula. 



A specimen of 12 mm. has the abdomen relatively short, the anus 

 still remote from the anal fin. The pelvics are in the form of small 

 tlaps on either side of, and a little above, the anus. A conspicuous fold 



