February 15, 1907] 



SCIENCE 



211 



generation of any of its appendages. The 

 crushing or the toothed forceps, when severed 

 at the ' breaking plane,' are replaced by their 

 like in due time after one or more molts. 

 How, then, are we to explain the anomaly of 

 similar elapfS? It seems highly probable that 

 the reversal, which regularly takes place in 

 Alpheus when its great 'hammer' claw' is cut 

 off, does actually occur, though but rarely, in 

 the lobster, or rather that it involves one side 

 only, there being no immediate compensatory 

 change to restore equilibrium of the system 

 of which the great claws form a part. Thus, 

 when a ' club ' claw is ' shot ' or amputated by 

 the experimenter, a chela of similar crushing 

 type is usually regenerated in its stead, but 

 rarely a toothed claw appears. There is a re- 

 versal of the appendage, bringing about an 

 abnormal condition of symmetry, but the proc- 

 ess stops here, and we have as the result lob- 

 sters with similar toothed claws, like the speci- 

 men illustrated in my earlier work referred 

 to above. 



In like fashion the toothed claw of the lob- 

 ster is usually replaced in regeneration by a 

 limb of similar type, as is the rule with 

 Alpheus, but in rare cases a reversal occurs 

 here also ; a ' club ' claw appears, and we get 

 a lobster with symmetrical crushing chelte, 

 like the specimen described by Dr. Caiman. 

 As this ease is, for the present, essentially 

 unique in the literature of the subject, we 

 may be sure that it is much rarer than re- 

 versal from crushing to toothed claws. There 

 is the possibility that these abnormal condi- 

 tions of symmetry may be upset by a compen- 

 satory change in the appendage of the opposite 

 side, but there is no evidence at present that 

 this ever takes place. 



In the first case the reversal from crushing 

 to toothed claw happens to reproduce the 

 primitive form of limb, but we see no reason 

 for regarding this as a case of reversion to an 

 ancestral stage, in the sense in which Stahr 

 uses the phrase. 



The explanation just offered is based on the 

 assumption that regeneration, following loss, 

 actually occurs in these cases. If there has 

 been no regeneration, we must then fall back 

 upon the view that as asymmetry in the great 



forceps is normally produced by changes which 

 take place in the egg, so the rare condition of 

 sy mm etry in these appendages may be casually 

 brought about in the same way. 

 ' - Francis H. Herrick 



BioLOGiCAi, Laboratory, 

 Western Reserve University 



CURRENT NOTES ON METEOROLOGY 



THE WEATHER OF SAXONY 



That portion of the Deutsches Meteorolo- 

 gisches Jahrbuch for 1902 which relates to 

 the kingdom of Saxony (Dresden, 1906) con- 

 tains a discussion of the special observations 

 made at the meteorological stations in that 

 section with a view to furnishing information 

 regarding the general weather conditions, for 

 use in forecasting. In addition to the regular 

 observations made thrice daily, the observers 

 note the prevailing type of weather during the 

 morning, afternoon and evening, according to 

 a scale of ten. These types differ somewhat 

 in summer and in winter. They are simple; 

 are noted by means of symbols, and have been 

 found to serve very well in giving the fore- 

 caster an excellent general view of the pre- 

 vailing weather over the kingdom. Such a 

 scheme might well be adopted among the vol- 

 unteer observers in this country and elsewhere, 

 and would often serve to give a clearer idea 

 of the weather conditions than do the regular 

 meteorological observations taken twice a day. 

 A second paper, on the dependence of weather 

 in Saxony on the prevailing weather condi- 

 tions of Europe, will be found useful in de- 

 tailed studies of European climatology. 



RAILROAD BUILDING IN ARID REGIONS 



The climatic difficulties now being met 

 with in the construction of the new railroad 

 between Damascus and Mecca are naturally 

 similar to those previously encountered in 

 other arid regions. The main line is being 

 built across a desert highland where for hun- 

 dreds of miles there are no permanent human 

 settlements within thirty to fifty miles of the 

 track. The country from Damascus 'to Medina 

 is inhabited only by small bands of nomadic 

 Bedouins. The scarcity of water is giving 

 serious trouble. Some new artesian wells 



