103 



bright pebbles or fragments of fctone. When the material the fish rests on is fine, like 

 sand, or contains an admixture of fine particles, a thin layer of the finer material 

 remains on the back of the fish when it emerges and moves about ; the fine particle 

 are retained on the skin partly by the adhesive property of the viscid mucus which 

 exists on the skin of all fishes, and partly by the minute spines of the scales The 

 sole thus moving gently about with its upper side covered with sand is partially 

 concealed, often only its actual movement betrays its existence. 



Solea lascaris is a rare fish in the neighbourhood of Plymouth. For a long time I 

 never met with a single specimen. The fishermen did not seem to know it by any of 

 the vernacular names given in books. The first specimen I obtained was discovered 

 by the Laboratory fisherman among a number of common soles exposed on the fish 

 quay for auction. He selected it on account of its peculiar appearance, after I had 

 described the species to him and requested him to search for specimens. The 

 fisherman to whom it belonged when asked its name said it was a " sand-sole." I 

 could not ascertain accurately where this specimen was taken, but it probably was 

 caught a long distance from land towards the central region of the channel. On 

 June 17, 1889, 1 trawled at night in Whitsand Bay for the purpose of obtaining if 

 possible young specimens of the common sole. In the products of this trawling I 

 discovered on my return three small specimens of Solea lascaris measuring 7|, 7^, 

 6f inches (19 cm., 19 cm., 17 cm.), respectively. The depth of water where these 

 were taken was three to five fathoms, the bottom a fine clean sand of light yellow, 

 almost silvery, colour. 



Solea varieyata, the thickback, is very common off Plymouth, but only in deep 

 water. I have never met with a specimen in or near the Sound, either young or 

 adult. On April 19, 1889, when I was on board a trawler fifteen or sixteen miles 

 S.~W. of the Eddystone, 213 thickbacks were taken in a single haul of the trawl. On 

 the Mount's Bay ground they are much less plentiful. 



Half-grown specimens of Solea lutea are fairly common in Plymouth Sound, but I have 

 never found adults there. The only adults I have seen were obtained from deep 

 water by a larger trawl, and the exact locality was not recorded. In the Sound the 

 young specimens, one to two inches in length, are especially abundant in Cawsand Bay, 

 in three to five fathoms of water on a bottom of fine sand of a dull grey colour. I have 

 frequently taken half a dozen there in a single haul of the shrimp trawl, together with 

 young scald-backs (Arnoglossus laterna). The shrimp trawlers believe both these fish to 

 be the young of the common sole. 



I have not been able to keep thickbacks alive in the aquarium, but there are living 

 specimens of the lascaris and lutea in our tanks, and they do not differ in their habits 

 from the common sole. 



There is no doubt, then, that the common sole lives naturally on ground consisting of 

 sand or gravel or other loose material, and that it has the instinct of seeking 

 concealment by burying itself beneath the surface of the ground by a rapid shaking of 



