260 



SCIENCE- GOSSIP. 



Wiltshire and Dorsetshire remains, it is not my 

 intention to discuss in the present article. 

 Although these beds are mainly of fresh water, or 

 at the most of brackish origin, possibly pointing to 

 nearness of land, it must not be overlooked that 

 there is a break pointing to a change of conditions 

 at one period of then- formation. Of Cainozoic 

 types there is a paucity ; but these, few as they are, 

 are of interest in still further exhibiting a con- 

 tinuity of development on the lines of our existing 

 cockroaches, more especially in the thickening of 

 the forewings or tegmina, which now approach to 

 an almost exact likeness of those borne by present 

 members of the family. 



Our British cockroaches lack the beautiful 

 colouring often displayed by others in different 

 quarters of the globe. In Corydia petitreriana, for 

 instance, which I lately received from Madras, the 

 under-wings and sides of the abdomen are bright 

 orange, the deep black elytra being boldly deco- 

 rated with seven large cream-coloured spots. 

 Panestliia javanica, from Sumatra, has its upper 

 surface pleasingly relieved by two yellow triangular 

 patches. Neither can we boast of so many species 

 as would probably be the case were our climate 

 less fickle and our winters less severe, for the 

 Blattidae are lovers of warmth and are only 

 numerous in tropical regions. Although a few are 

 indigenous to our islands, it is with an introduced 

 species, Blatta (Stilopyga) orimtalis (figs. 11, 12, 



15, and 16), we are mostly familiar. This is the 

 ubiquitous " blackbeetle " of our kitchens and 

 cupboards, which insect, although now generally 

 known by the latter name, it is scarcely necessary 

 to remark, is neither black nor a beetle at all. The 

 colour of this household pest is of a warm dark 

 ruddy brown, save where its chitinous covering is 

 thinnest, when it partakes of a brighter amber hue, 

 whilst it belongs to the Orthoptera and not to the 

 Coleoptera, the former family once forming the 

 order Dictyoptera of Leach. Our word " cock- 

 roach" is derived from the Spanish cucardcha, 

 which signifies both cockroach and wood-louse ( ls ), 

 the former portion of the word being in turn 

 traceable to the Latin coccum, a berry, the diminu- 

 tive termination -delta denoting mean or con- 

 temptible (Jas. M. Miall), so that the whole term 

 is capable of a somewhat free rendering as a " con- 

 temptible little berry." The habit of the wood-lice 

 of rolling themselves into balls is well known, and 

 the term may have been first applied in the case of 

 the cockroaches in connection with the oothecae 

 or egg-purses (figs. 7 and 14), which in many species, 

 as in our common " blackbeetle " for instance, 

 certainly bear a superficial resemblance to seeds 

 or berries, more especially after exposure to the 

 air has imparted to them their dark brown hue. 



(13) " Standard Diet, of English Language," 1900, vol. i. 

 p. 362. 



{To be continued.') 



STUDY OF A LOWER ORGANISM. 



By Harold A. Haig. 



TT frequently happens that whilst seeking for 

 -*- some object under the microscope the searcher 

 comes across various animalcula whose sizes range 

 from the minute dot that is seen darting about in 

 all directions, apparently without any fixed pur- 

 pose, to those of more considerable dimensions that 

 move less rapidly and appear, from their constant 

 presence near filaments of algae, to be looking for 

 food. 



Now, many of these organisms are to be found 

 in preparations of pond-water where Spirogijra or 

 Vaucheria abound ; one of them, Paramoeeium, is 

 particularly interesting, both on account of the 

 ease with which observations may be made upon 

 it, and also the fact that it is unicellular, bringing 

 us down to some of the fundamental problems of 

 cell-life. With a microscope giving a magnifica- 

 tion of some 600-700 diameters we may make out 

 all that we require. It is best to study the living 

 organism ; but we may also " fix " it, if necessary, 

 by slightly warming the slide over a gas-flame. 

 The latter method is often employed where 

 structural details are under observation. 



If we focus the body of this animalcule ( l ) into 

 different planes we may determine that it is made 

 up of (i.) a firm outer layer that has been called 

 the " ectosarc " ; and from the motions of certain 

 particles inside this outer layer we argue the exist- 

 ence of (ii.) a more fluid inner portion or " endo- 

 sarc." Both of these are protoplasmic in nature, 

 and the whole organism is thus comparable in 

 gross structure with an amoeba in which we see 

 the same two subdivisions into " ectosarc " and 

 " endosarc." 



The greater part of the surface of the body is 

 covered with a number of whip-like processes, or 

 cilia, which are in continual movement. It is by 

 means of these that the organism is propelled 

 along in the medium in which it lives. We shall 

 return later to the peculiar motion that each cilium 

 presents if closely watched. If we view the lateral 

 or broader surface of the body, we shall notice 



(1) It may be here mentioned that in form Paramoeeium is- 

 oval and bilaterally compressed, so that if viewed edgewise it 

 is spindle-shaped. (See fig. 1.) The surface of the body pre- 

 sents longitudinal striations. 



