254 



HARDWICKE'S S CIENCE-GOS SIP. 



fius, which have large fulcral scales on their front 

 margins, are paired but not lobed. 



The fish that I am describing (fig. 172) {Palceo- 

 niscus Egertoni (?) is a small one, its length being 

 about two inches and a half, and its depth seven 

 lines. Its body iscoveredwith small scales (fig. 175), 

 which are covered with strongly defined and irre- 

 gular ridges and furrows, the former terminating in 

 sharp cusps on the hinder or free margins. It is 

 remarkable for the large and flowing form of the 

 dorsal and anal fins, the former of which contains 

 about twenty-five rays, of which the four or five 

 hinder ones increase in length in succession from 

 before, forming an ornamental border to the fin. 

 The upper lobe of the tail is remarkably long and 

 attenuated, and is covered with small scales to its 

 extremity. 



Fig. 1/6. Scale of CxUicanthus lepturus; a, nat. size ; 

 b, ditto magnified. 



Associated with the scales of Talmoniscus I found 

 a scale of Calacanthus lepturus (fig. 17G). This fish 

 is a Lepidoganoid, but belongs to another sub-order, 

 the Crassopterygid^e, the members of which are dis- 

 tinguished by having hollow fin-spines, two dorsal 

 fins, each supported by a single interspiuous bone, 

 cycloid* overlapping scales, two jugular plates, and 

 by the remarkable peculiarity of the swim-bladder 

 being ossified. 1 have also found this fossil in the 

 Derbyshire coal-measures. 



The third fossil mentioned, Acanthodes, also 

 belongs to the same order as the preceding ones, 

 but has been placed in the sub-order Acantho- 

 didce. This fish was covered with small shagreen- 

 like scales, and was armed with strong spines 

 simply implanted in the flesh (fig. 174) at the 

 front of each fin, of which it had four ; viz., one 

 dorsal, one pectoral, one ventral, and one anal : it 

 had also a heterocercal tail. Moreover, it had not 

 any distinctly ossified cranial bones, and no oper- 

 culum . 



Such is a brief description of three of the fishes 

 that roamed in the waters of the Carboniferous 

 age. On a future occasion I hope to return to the 



subject, and describe other forms of piscatory life 

 that illustrate the wisdom and benevolence of the 

 Creator. Rev. W. H. Painter. 



Derhj. 



PHOST PHENOMENA. 



DURING a recent hoar frost I observed the 

 following rather curious phenomena. 



It was a perfectly calm morning ; even the light 

 twigs of the birch hung motionless. It must have 

 been as calm all nighi, for the frost-crystals stood 

 , thick on every spray, and many of them were half an 

 inch in length. The world at midsummer is not 

 more beautiful than on such a morning. But it 

 struck me as remarkable that all these crystals 

 pointed in one direction, nearly south-east. The 

 south-east side of every twig on tree or hedge, of 

 every brown bent in the pastures, of every blade of 

 grass by the M^ay-side, was fringed as with the teeth 

 of an ivory comb, while the north-west side was 

 entirely bare and dark. It looked as if a north-west 

 wind had been blowing and had driven them all 

 before it. But there was no wind at all ; had there 

 been any, the whole fairy fretwork would have been 

 shaken to the ground. By means of that dehcate 

 anemometer, a wetted finger, I found, however, that 

 there was the slightest possible air-current from the 

 south-east, and a moment's thought showed clearly 

 that such crystals must always face the current. 

 They are built up by the successive congelation of 

 minute particles of water floating in the air. If the 

 air is absolutely quiescent these particles will slowly 

 fall towards the earth and the frost-crystals will 

 stand erect. If there is a slight current the particles 

 of water will be carried by the current, laid one by 

 one on the points of the incipient crystals, and 

 freezing instantly will build them up in the very 

 teeth of the stream. 



Coming to a level crossing over a railway, I noticed 

 a peculiar twinkling of light among the telegraph 

 wires. There>ere three wires,— two above at equal 

 heights and one below. They were all regularly 

 fringed with frost-crystals on one side, and I could 

 see them for a quarter of a mile down the line. 



The twinkling light was caused by a very slight 

 motion of the two upper wires ; the lower wire was 

 perfectly at rest. I asked myself, what could cause 

 the motion of the two upper- wires without moving 

 the third ? The tension of all three appeared to be 

 about equal. The motion was not confined to a 

 single interspace between two posts; it extended 

 uniformly, as far as I could see, and the lower one 

 was everywhere at rest. It was not a lateral vibra- 

 tion, either perpendicular or horizontal, but a partial 

 rotation on the longitudinal axis of the wire. I 



* Cycloid scales consist of thin, flexible, homy plates, 

 circular or elliptiral in shape, and have a more or less 

 completely smooth outline. 



watched it for about ten minutes. It continued 

 with uniform velocity during the whole time, and 



