114 



HARDWICKE'S SCIENCE- GO S SIP. 



that many forms now considered as belonging 

 to the same genus, must, if this arrangement be 

 adopted, be separated. Eor example, Tricerutium 

 Montereyii, and at least two species of Stictodiscus, 

 cannot be with propriety retained in their respective 

 genera. In these species the two valves of the 

 frustule are unsymmetrical; one of them being 

 bullate at the centre, and the other fiat, or only 

 slightly convex. The genera included ill this part 

 are the following : Melosira, Lysigonium, Podosira, 

 Orthosira, Cyclotella, Coscinodiscus, Arachnoid iscus, 

 Actinoptychus, Craspedodiscus, Omphalopelta, Actino- 

 cyclus, Eupodiscus, Auliscus, Odoutodiscus, Bid- 

 dulphia,Triceratium t Ampkitetras, Trinacria, Istkmia, 

 Fragilaria, Penticula, Odontidium, Pimeregramma, 

 Plagiogramma, Piatoma, Ralfsia, N.G., Rhaphoneis, 

 Synedra, Grammatophora, Tabellaria, Tetracyclus, 

 Rhabdonema, Striatella, Tessella, Amphvpleura, Mas- 

 togloia, Pic/cieia, Collectonema,PerIceleya, Schizonema, 

 Piadesmis, Prebissonia, Navicula, — in all forty-three 

 genera. It will be observed that the author has 

 reinstated the old genus Lysigonium to receive the 

 following forms:— Melosira nummuloides, M. Westii, 

 and Lysigonium Wrightii. The genus Trinacria is 

 given as an Irish diatom on the authority of a 

 single specimen found in a mounted preparation 

 from the Arrau islands. As this is a fossil form, 

 occurring in abundance in the Mors deposit," 

 it is probable that the single valve was an inter- 

 loper. I may here remark that T. regina is 

 identical with Triceratium, solenoceros, Ehr., and 

 and T.' Kittonianum, Grev. I fear Craspedodiscus 

 and Arachnoidiscus have as little claim to a place 

 among English or Irish diatoms, as the preceding 

 species. The N.G. Ralfsia must be deleted, as there 

 is already a genus of marine alga; (belonging to the 

 family Mesoglocaceaj), bearing that name {see 

 Kiitzing's "Species Algarum," p. 543). The text 

 occupies 190 pages, and there are 9 plates, contain- 

 ing 329 figures. We are sorry that little can be 

 said in their favour : in many instances they are 

 simply misleading. To justify these remarks we will 

 give the following examples : Synedra superba, with 

 costse as distant as those on Pinnularia alpina ; 

 Coscinodiscus centralis, with large, distant, monili- 

 form markings ; Navicula cardinalis, with the mar- 

 gins inllated (all our specimens have the sides per- 

 fectly straight). The text will be found generally 

 accurate, and the descriptions are brief but lucid 

 and it is very much to be regretted that some com- 

 petent artist could not have been found to give 

 tolerably accurate figures of the forms described in 

 the book. The art of representing diatomaceous 

 forms seems to be lost in this country. — F, Kilton. 



The " Eozoon Canadense." — In iheA?inals and 

 Magazine of Natural History for April there is a 

 capital translation, by Mr. W. S. Dallas, E.L.S., 

 of Otto Hahn's "Micro-geological Investigation of 



Eozoan Canadense" the "Dawn animalcule" of the 

 Laurentian rocks. Otto Halm considers it in its 

 geological, zoological, and mineralogical bearings, 

 and comes to the very definite conclusion that the 

 Eozoon is a myth, founded on mistaken conclusions 

 as to the micro-geological characters of certain 

 serpentines. 



Polarization of Living Tissues.— Some time 

 since, while examining the coutents of a "micro- 

 scopic " aquarium, I tried the effect of the polari- 

 scope on the Daphuia pulex, expecting to find 

 the shell would polarize in a similar manner to the 

 ova of the oyster. I was very much surprised to 

 find the shell not affected, but the body itself; the 

 intestines and muscles of the tail and antennse 

 showed a greater intensity of colour than almost 

 any object I had ever seen polarized. I have at 

 different, times examined several specimens of Crus- 

 tacea, Cypridina, Polyphemidee, &c., and always 

 with the same results. The young of many water- 

 beetles are also good examples ; in fact, from the 

 observations I have made, I think there is no doubt 

 that living tissues generally will polarize in some 

 degree. The leaves of many aquatic plants examined 

 while living form very striking objects for the 

 polariscope. — W. C. PL. P., Ives. 



Experiments on Spontaneous Generation. — 

 In the Popular Science Review for April there is a 

 capitally- written and well-illustrated article by the 

 Rev. W. 11. Dallmger, already well known for his 

 researches in the life-history of the monads, giving 

 a review of Professor Tyndall's "Experiments in 

 Spontaneous Generation," and Dr. Bastian's posi- 

 tion thereto. The author thiuks that as to the 

 development of Pacteria in infusions charged with 

 solid matter, precise experiment of a sufficiently 

 comprehensive character has yet to be made on 

 them in relation to the demonstrated germs. Mr. 

 Dallinger sums up against Dr. Bastian's theory. 



ZOOLOGY. 



Camberwell Beauty. — On Friday, March 10th, 

 a female Camberwell Beauty {Vanessa Antiopa) 

 was caught near Padiham, Lancashire, by Mr. 

 V. H. Lucas, being the first ever known to be 

 caught in this neighbourhood. — W. Wilcox. 



Natural History Abroad.— In an exceedingly 

 well-written and scholarly article which appeared 

 in the Fortnightly Revieio for January, we have a 

 good illustration of the usefulness of how even a 

 slight knowledge of Natural History might prevent 

 an author from committing egregious blunders. 

 The writer, speaking of the passive endurance of 

 the lower animals to pain, treats us to the follow- 

 ing : — " We are all familiar .... with narratives 

 of moths, having pins in their bodies, which have 



