The Flatties 



could not describe even a single fish. There weren't enough words 

 in the language, not in their language at any rate. What, for ex- 

 ample, were they going to call the bit of bone that came down the 

 head to hide the gills? *An operculum', muttered the master. 

 And the holes in the top of the head ? 'Spiracles. ' And the shape 

 of the tail that was divided into a large banner-like upper section 

 and a smaller triangular one on the lower part of the body? *A 

 heteroceral tail.' And so on, until Agassiz was satisfied that they 

 were interested enough in the things that words described to de- 

 serve a grounding in the vocabulary of ichthyology. Then he would 

 begin his wonderfully patient disclosures of the functional and 

 evolutionary importance of slight anatomical differences, the 

 position of a fin, the shape of a tooth, the texture of a scale. But 

 Jan did not have the help of Agassiz' learning. He had to make his 

 own interpretations. 



One small point interested and puzzled him for a long time. 

 For hours on end he studied the mouth of a lemon sole. It diff- 

 ered radically from the mouths of all the other fish landed at Aber- 

 deen. It was not straight and lean, like the mouth of a snake. Most 

 other fish had mouths like snakes, not really the same, of course, 

 but still they were straight and they stretched back lipless as they 

 do in snakes. But the lemon sole had lips, thick tubular lips of 

 bright flesh, encircling a small round mouth. .There was mucus 

 too, lots of it, but then the whole body of the lemon sole was 

 covered in mucus, a thick slippery skin of mucus, so that there 

 was perhaps no significance in the mucus round the lips. He 

 would look all round the market, trying to find something that 

 resembled the mouth of the lemon sole. But there was nothing. 

 Not, at least, until one day when he noticed the auctioneer purs- 

 ing his lips over a pencil as he wrote down figures in a notebook. 

 His mouth too became round, and Jan could see the mucus glist- 

 ening on the inner surface of his lips. But what could it mean ? It 

 was no accident. Jan was sure of that, for he had studied enough 

 biology by this time to know that evolution eliminates accidents 

 unless they serve a biological purpose. But what could it mean? 



107 



