144 



few moments, to recognize it. The next day, a few dusky, green and grey 

 markings like those of the loach, were distinctly seen extending from the 

 base of the candal fin to the vent, the tail and other fins also becoming 

 suffused with a faint olive yellow. In the course of two or three days, it had 

 apparently become reconciled to its position, and resembled very much a 

 loach in all its markings and colours, except that whilst the fins became 

 sprinkled with dusky spots, arranging themselves in faint, ill-defined trans- 

 verse bars upon them, the rays assumed a brownish yellow tint, and it stood 

 revealed as an unmistakeable Goby. We have kept chameleons for many 

 months together, we know therefore what we are about when we state that we 

 have never witnessed greater changes of colour in the chameleon, than in 

 tliis little fish, not referring, of course, to the difference of time in which 

 each creature eff'ected its changes. Under these circumstances, after 

 having carefully compared the descriptions of Couch and Yarrell, of all 

 the Gobies kno^vn to them, we feel inclined to suggest that the Gobius 

 minutus of Yarrell, and the Gobius pellucidus of Couch may be merely the 

 same fish seen under differenit conditions. 



At intervals, still fm-ther fi.-om the river, we meet with other shallow 

 excavations in the soil, (made apparently for the purpose of retaining 

 water for the use of cattle,) totally unconnected with any water-course, 

 and entirely dependent for their supply of moisture, upon rainfalls, or the 

 overflow of the Severn. They can be replenished from the latter som-ce, 

 but seldom, so far as our experience extends. 



The water which they contain is slightly brackish, but so is invariably 

 that which rises from the Uassic strata in the neigbourhood, when newly - 

 pierced, and it so continues until by long-continued percolation of fresh 

 water, the saline elements from the contiguous soil have been dissolved and 

 exhausted. Presuming these small ponds to be chiefly dependent for their 

 water-supply upon rainfalls, we may readily conceive that their brackishness 

 is derived from the salt of tidal origin, inherent in the silt of which the 

 grounds are formed, dissolved by similar processes. 



None of these ponds afford traces of native vegetation, with the 

 exception of a few fronds of the Bladder ulva, jEnteromorjyJia intestinalis, 

 which subsequent examination shows us to be covered with rare 

 diatomacese, particularly Navicula hijipocampm of large size and 

 rich colour, in full activity; no Hydrohii, Gyrini, or other insect, 

 and with the exception of a small annelid or larva, whose presence was 

 evident from the small spots, in paii's, upon the sui-face of the mud, but 

 which we otherwise failed to detect, no other life than that which we 

 have already described, could be traced in their waters. 



Here then, again, we find ourselves in a transitionary state of things 



