摘要:

Summary.1The Symphyla and Pauropoda live in crevices in soil and woodland litter. Both are vegetarian and incapable of forcing a passage through the substratum.2The habit of Symphyla to twist and turn in any plane, without the body distortions shown by Onychophora, appears to have been the main determinant of the principal features of trunk construction, enabling these animals to penetrate deeply without pushing.3Pauropodan trunk structure is correlated with the ability to use fast patterns of gait, but the stepping is not rapid. The necessary trunk rigidity is associated with a short body, manoeuvrable as a whole without much flexure.4The Symphyla achieve speeds of running which, in relation to their size, are comparable with those of fast‐moving Chilopoda. But fleetness is obtained in a most unusual manner, by combination of slow patterns of gait with very rapid stepping. Such movements result in great stability and are compatible with extreme flexibility of body. The Pauropoda, with very few legs in contact with the ground at any one moment, are very unstable, but they can maintain rigidity.5Cuticular features promoting:— (i) trunk flexibility in Symphyla are: the posterolateral lobes on the tergites; intercalary tergites; extra tergites on trunk segments 4, 6 and 8 in Scutigerellidae and on at least segments 4, 6, 8, 10 and 12 in Scolopendrellidae; and the paired sternites well‐separated longitudinally; and (ii) cuticular features promoting trunk rigidity in Pauropoda are: the extreme heteronomy in tergites; and a chilopod‐like sternal region, although little sclerotized.6Trunk musculature promotes:– (i) flexibility in Symphyla by: the short dorsal longitudinal muscles; the absence of deep dorso‐ventral and oblique muscles; the large superficial pleural muscles; and the elaborate short sectors of the ventral longitudinal muscle associated with the coxal apodeme; and (ii) rigidity in Pauropoda by: the long dorsal longitudinal muscles; the well‐developed deep dorso‐ventral and oblique muscles, muscledvmp.being extremely long and oblique; the absence of superficial pleural muscles; and the form of the ventral longitudinal muscles.7The functional interpretations of skeleton and musculature given here tally with those already put forward for Chilopoda and Diplopoda.8The general form of the coxa and its movement on the body in Symphyla and Pauropoda resembles the Chilopoda in showing a promotor‐remotor swing and a parasagittal rock on the body. Symphyla in addition show slight adductor‐abductor movements. The skeleto‐musculature causing these movements resembles that of Chilopoda in principle but differs in some details.9The skeleto‐musculature of the telopod of Pauropoda and Symphyla are shown to be correlated with the different types of gait employed and with other requirements of these animals. A basic similarity is shown by the telopods of all Myriapoda, the differences being correlated with functional needs.10A fundamental difference between the morphology and modes of action of the coxa‐sternite articulation of myriapods and the coxa‐pleurite articulation of pterygote insects suggests a deep‐seated evolutionary dichotomy which has resulted in the contrasting features of the whole leg in these groups.11The potential for the evolution of a few pairs of legs on a many segmented body, and for some of their extrinsic muscles to be convertible into flight muscles, is associated with the pterygote type of coxa‐body articulation. These advances could not have originated from the myriapodan type of coxa‐body articulation and all that depends upon it.12Evidence is summarized in support of the concepts of:— distant phylogenetic unity between the Onychophora, Myriapoda and Hexapoda; independence of pterygote insect origin from the Myriapoda; and of parallel evolution of the four classes of Myriapoda.13Support is given once more for the view that the Onychophora‐Myriapoda‐Insecta assemblage could not have originated either fro

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1966.tb00501.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Summary.The protozoanEnteromyxa paludosaCienkowski, not recorded since its original description in 1885, has been refound in the English Lake District. The general account of its life history described so long ago is confirmed and many new observations have been made.Enteromyxais now known to be multinucleate, the nuclei being of a vesiculate type. In addition to the broken‐down algal pigment spheres coloured bluish‐green or green the body contains numerous contractile vacuoles and small granules. Very rarely non‐contractile vacuoles are seen.Its food, threads ofOscillatoria, is captured by elongate processes produced from the external hyaloplasm. Once a process has made contact and become adherent to a thread, the process contracts and the thread is slowly drawn towards the body which it then enters by way of a large hyaline bulge. Once inside the animal disintegration of the alga is rapid.The method of formation of the endocysts is described in detail. The product of excystment from an endocryst, hitherto unknown, is a small uninucleate amoeba‐like organism, one from each e

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1966.tb00502.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Summary.This paper describes some parasitic copepods of marine fishes from the collection of the Zoological Institute of the Academy of Sciences, Leningrad, U.S.S.R. The descriptions and data are given of 21 species and two subspecies of copepods, belonging to 17 genera. The descriptions include one genus (Lateracanthus), five species (Caligus sensilis, Chondracanthodes tuberofurcatus, Parapharodes semilunaris, Lateracanthus quadripedis and Lernaeopodina pacifica) and two subspecies (Eubrachiella gaini dorsituberculataandDendrapta cameroni longiclavata) new to science.

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1966.tb00503.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY