128 



NATURE 



{Dec. 13, 1877 



and is thus described by that gentleman : — It consists of 

 a mass of mycelia and zoosporangia (or oogonia). Be- 

 ginning with the mycelium, a close examination shows 

 that it is furnished with numerous joints or septa. If, 

 therefore, any reliance is to be placed upon the modern 

 distinguishing characters of the now living species of the 

 genera Peronospora and Pythium, as furnished by a 

 septate or non-septate mycelium, the fossil parasite 

 belongs to the former, and not to the latter genus, nor to 

 any of the Saprolegnicce. The oogonia do not agree 

 with those of Cystopiis. Within many of the fossil oogo- 

 nia the differentiation of the protoplasm into zoospores 

 is clearly seen ; but if any doubt could exist as to the 

 exact nature of this differentiation, then other oogonia (or 

 zoosporangia) on the same slide show the contained zoo- 

 spores with a clearness not to be exceeded by any living 

 specimens of the present time. It is a very remarkable 

 fact that the oogonium precisely resembles, in size and 

 other characters, average oogonia of the present day, 

 especially those belonging to Peronospora infestans. The 

 contained zoospores are, moreover, the same in form and 

 dimensions with those of P. infestans when measured to 

 the ten-thousandth of an inch. The organisms are, in 

 fact, apparently identical ; and the average number of 

 zoospores in each oogonium is also the same, viz., seven 

 or eight. The aerial condition of the fungus has not yet 

 been observed. Mr. Worthington Smith suggests, in 

 conclusion, that we probably have, in Peronosporites 

 antiqiiarius, one of the primordial plants from which 

 both the great families of fungi and algae may possibly 

 have descended ; but should not this primordial plant have 

 led a non-parasitic life 1 — for if parasitical, then this fact 

 points to some pre-existing plant. 



The Laws of Digital Reduction.— Hitherto there 

 has been little explanation of the curious variation in the 

 number and relative size of the digits in the vertebrata. 

 Mr. John A. ^yAtr {American Naturalisi, October) suggests 

 that the number of toes is least where the mechanical 

 strains are greavest, and impacts most frequent and severe. 

 He quotes several cases in which the hinder digits are 

 reduced more than those of the fore feet, and shows that 

 in all of them the body in jumping or running pitches 

 mainly upon the hind limbs. He looks upon the outer 

 toes of man as in process of undergoing reduction, being 

 now v/eaker and shorter than in any of the higher apes. 

 The chrysochloris among moles is an instance of special 

 reduction in the anterior extremity, and here the mecha- 

 nical strains are most frequent and severe. Among 

 fossorial animals the claws and toes are usually best 

 developed on the fore limbs. The retention by certain 

 groups, of digits in a very equal state of development in 

 manus or pes, or both, is attributed to the equal distribu- 

 tion of strains on all. 



The Birds of Guadaloupe Island.— This inter- 

 esting fauna is dealt with by Mr. Robert Ridgway in the 

 Bulletin of the Nuttall Ornithological Club for July. It 

 is strange that only eight forms from this island, situated 

 about 220 miles south-west of San Diego, are satisfactorily 

 known, and their affinities are almost entirely with those 

 of western North America. They are recognised by Mr. 

 Ridgway, however, as specifically distinct, differing from 

 their nearest mainland allies in the (i) increased size of 

 the bill and feet, (2) shorter wings and tail, and (3) darker 

 colours. 



The Distribution of Freshwater Fishes.— Dr. 

 D. S. Jordan, the well-known American ichthyologist, has 

 contributed to the American Naturalist for October some 

 of his conclusions derived from long study of the fishes 

 of rivers flowing in different directions, and under the 

 most widely- varied physical conditions. He finds that in 

 the case of rivers flowing into the ocean, the character of 

 the fishes of the upper waters bears little or no relation to 

 the place of discharge. The higher or the older the 



watershed between two rivers, the fewer species are com- 

 mon to both. Certain species (not including species of 

 general distribution) occur on opposite sides of even the 

 highest watersheds. When the watershed between two 

 rivers is a swampy district, the same species are found ia 

 the head waters of both, though the faunas of the lower 

 courses may be distinct. There is often a great differ- 

 ence between the forms in the upper and lower waters of 

 a river, owing to differences in physical conditions. Some 

 species are strictly confined to one river basin ; others 

 are widely distributed. Usually the more southern rivers 

 have the most peculiar and varied faunas. Species of 

 the widest distribution often have breaks in their range 

 which cannot be accounted for by any known facts. The 

 characteristically American forms of freshwater fishes 

 are, generally speaking, absent or rare in the waters of 

 New England and of the Pacific slope. The larger the 

 river-basin, the greater its variety of forms. Seventy 

 species have been taken in the little White River at In- 

 dianopolis, representing forty-eight genera, twice as many 

 as occur in all the rivers of New England. Other things 

 being equal, a river whose course lies in a region of 

 undisturbed stratified rocks, or of glacial drift, contains 

 most genera and species. Certain forms appear generally 

 distributed in a definite range, either without regard to 

 the direction in which the rivers flow, or even bounded 

 by parallels of latitude. In any river-basin the most 

 abundant species (of small fishes) are usually (i) those 

 peculiar to it, or (2) those of widest distribution. 



Earwigs (Forficulid^). — Linnaeus seems to have 

 known but two species of earwigs {Forficula au7-iculata 

 and minor). Both were European, and had Elytra dimi- 

 diata et AIcb tectce, and were placed among the beetles 

 (Coleoptera). There are nowabout 250 species known which 

 are found all over the world, and grouped in about thirty 

 genera, of which the genus Forficula is by far the richest 

 in species and the widest in its geographical distribution. 

 Happily, too, it still retains the two first-named species, 

 and it has also most justly given its name to the family. 

 Entomologists will be glad to know that Mr. Samuel 

 Scudder has just published a series of critical and his- 

 torical notes on this family, in which he gives descriptions 

 of all the known genera, and an alphabetical list with full 

 synonyms of all the described species ; this most valuable 

 list will make the study of these interesting insects an 

 easy one. It is published in Parts 3 and 4 of vol xviii. of 

 the Proceedings of the Boston Society of Natural History. 



Hungarian Spiders.— The first part of a work on 

 Hungarian Spiders by Assistant-Director Otto Hermann, 

 of Buda Pest, has just reached us. It forms a handsome 

 royal-quarto volume, with three plates, and is printed in 

 double columns, one in Magyar, and the other, fortu- 

 nately for us, in German. This volume forms part of the 

 T?'ansactions of the Royal Hungarian Natural History 

 Society, which is really to be congratulated on the 

 appearance of this and the next work that we will 

 mention. The present volume gives a sketch of the 

 literature belonging to spiders, and forms one of the 

 most generally interesting portions of the work, for it 

 is most carefully elaborated, being divided into the 

 bibliography of the older and the newer times. It 

 further treats of the life-history of spiders in general, and 

 of the geographical distribution of those species to be met 

 with in Hungary. The next volume will contain the 

 spiders met with in Hungary proper, 



Hungarian Rotifers or Wheel- Animalcules. — 

 A memoir on Hungarian Rotifers by Dr. Bartsch Samu is 

 also published under the auspices of the Royal Hungarian 

 Natural History Society, but it is v/ritten exclusively in 

 Magyar, if we may except a short appendix containing 

 brief descriptions of the new species determined by the 

 author, and therefore unfortunately we can do no more 

 than call attention to it. 



