Q2 FROM FISH TO PHILOSOPHER 



tional amounts. The paired kidneys are fused, and the 

 organ is anomalously appHed to the ventral, rather than 

 the dorsal, wall of the abdomen. Two ureters are pres- 

 ent, and each expands into a voluminous ear-shaped 

 bladder. The kidney possesses pine-cone-shaped glomer- 

 uli and contains *cavities lined with cihated epithehiun, 

 which are probably nephridial but the disposition of 

 which I have not yet been able to work out' (writes 

 MiUot). 



A single coelacanth fossil from the marine Jurassic fos- 

 sil beds of Solenhofen, Bavaria, presents a full-grown fish 

 containing within the body cavity the skeletons of two 

 small individuals of the same species. D. M. S. Watson, 

 after considering the possibiHty that these small fishes 

 may represent food, rejects this interpretation in favor of 

 the view that they are unborn embryos and that this 

 particular coelacanth was ovoviviparous. The evidence, 

 however, falls short of proof. Alternatively, the coela- 

 canths may have adapted themselves to salt water in 

 the manner of the recent marine teleosts— that is, by 

 drinking sea water and excreting the salt out of the gills 

 —but in this case we would expect them to have an 

 aglomerular kidney like that of many of the bony fishes 

 (Teleostei) discussed in Chapter VIII. We must await 

 further reports on Latimeria before we can imderstand 

 how this hving fossil invaded the sea. 



The record of the Amphibia in the Devonian, the period 

 that saw their early evolution, is very sparse— an incom- 

 plete skull from the famous Upper Devonian beds at 

 Scaumenac Bay in Canada and a few skulls from fresh- 

 water deposits in Greenland which may be either late 

 Devonian or early Mississippian in origin. These were 

 fair-sized animals with skulls half a foot or so in length, 

 and probably represent an advanced stage in amphibian 

 evolution. But in the succeeding Coal Measures of North 

 America seven amphibian orders, comprising 19 families, 

 46 genera, and 88 species, have been identified. Most 



