294 NATURAL SCIENCE. November. 



Scott. " An unprejudiced comparison," says he, " seems to me to 

 show nothing more here than a very remote parallelism, not 

 suggestive of affinity." " There is no reason to believe that the 

 Bryophyta, as we know them, were the precursors of the vascular 

 Cryptogams at all." " Things seem to point to both Pteridophyta 

 and Bryophyta having had their origin far back among some unknown 

 tribes of Algae." The utter hopelessness of attacking such a problem 

 is very forcibly put. It is generally agreed that Gymnosperms arose 

 somehow from the vascular Cryptogams. Yet in the far-off days of 

 the Devonian we find both flourishing together. " Hence, in the 

 Devonian epoch, there had already been time, not only for the 

 Pteridophyta themselves to attain their full development, but for 

 certain among them to become modified into complex Phanerogams. 

 It would not be a rash assumption that the origin of the Pterido- 

 phyta took place as long before the period represented by the plant- 

 bearing Devonian strata as that period is before our own day. Can 

 we hope that a mystery buried so far back in the dumb past will be 

 revealed ? " 



A Nesting Fish [Amia calva). 



In his valuable account of the early development of Amia calva 

 {Quarterly Journal of Microscopical Science, vol. xxxviii., p. 413), 

 Dr. Bashford Dean describes the curious nesting habits of that 

 archaic fish. In the beginning of spring the fish leave the deeper 

 waters of the lake and sun themselves in the shallow, swampy ends, 

 where Chara, Potamogeton, and bulrushes abound. Immediately 

 before spawning the fish divide themselves into parties, each consist- 

 ing of a female and several males. The nest is prepared some time 

 before spawning. Its method of construction is doubtful : "fishermen 



state that the spawning party prepares it by constant circlings 



the soft weeds and rootlets appear bent and brushed aside in a way 

 that gives it somewhat the appearance of a crudely-finished bird's- 

 nest." The spawning fish leaves the nest from time to time, returning 

 in company, and the eggs and milt are shed simultaneously. The 

 eggs, after being fertilised in the water, become instantly adhesive, 

 sticking to the roots of the water-plants. The early stages of 

 development are rapid, the larvae all disappearing from the nest 

 twenty-four hours after the eggs are laid. 



A curious feature is that the male acts as guardian of the nest 

 and caretaker of the young. Soon after all the eggs are laid, a single 

 male takes his position on the nest, and his constant movements no 

 doubt aid in keeping the eggs free from sediment, and duly supplied 

 with oxygen. The larvae leave the nest in a body, and presently 

 appear as a dense swarm swimming under and around the male. The 

 male remains with them for some time, gradually leading them away 

 from the breeding ground, and during this period he is most zealous 

 and courageous in their defence. 



