4^2 



NA TURE 



[October 14, iqoo 



of the southern banks to the " overfalls " renders them 

 unsafe as oyster-beds, although the actual modus operandi 

 by which this is brought about is not at present under- 

 stood. 



In a note communicated to vol. xxxiii., No. 3, of the 

 Tropical Agriculturist, Mr. E. E. Green states that an 

 attempt is to be made to check the ravages on tea-plants 

 in Ceylon of the beetle known as the " shot-hole borer " 

 by introducing a predaceous beetle {Clerus formicarius), 

 which is already well known as an enemy of pine-boring 

 Scolytida3. Mr. Green decided to try this beetle as an 

 exterminator on account of the good reports of its value 

 as a pest-ridder received from the United States. The 

 experiment can, however, only be of a tentative nature, 

 as the Clerus is an inhabitant of the temperate zone, and 

 it. remains to be seen whether it will thrive in the tropics. 

 Iq a second note the Government entomologist states that 

 in the Ambawella district of Ceylon camplior-plants are 

 attacked by a scolytid allied to the shot-hole borer. 



Several interesting additions to the British insect-fauna 

 are recorded in the October number of the Entomologists' 

 Monthly Magazine. Many years ago, it appears that Dr. 

 David Sharp received from Chobham a water-beetle which 

 he vvas unable to ' identify ; this year he took a second 

 example at Brockenhurst, and he finds both to belong to 

 the continental Laccobius scutellaris. In the ne.xt article 

 Mr. J. Edwards describes a new beetle from Horning, 

 under the name of Dryops anglicus ; later on, Mr. E. R. 

 Speyer records the occurrence in Sussex of a number of 

 specimens of the continental dragon-fly Somatochlora 

 metallica, a species already known from Scotland, but not 

 hitherto definitely identified in England. Finally, Mr. 

 K. J. Morton mentions the occurrence in the west of Ireland 

 of the trichopterid Limnophilus fuscinervis, which is quite 

 new to the fauna of the British Isles. 



C. D.^WYDOFF contributes to the Zeitschrift fiir -wissen- 

 schaftliche Zoologie (Bd. 93, Heft 2) a very elaborate 

 memoir on the process of regeneration in the Entero- 

 pneusta. He considers that this group of animals, about 

 which so much has been written recently from the morpho- 

 logical and phylogenetic points of view, affords an un- 

 commonly convincing example of the untenability of 

 Weismann's view that the power of regeneration is the 

 result of natural selection. He states that when dredging 

 for Ptychodera only the anterior portion of the body is 

 usually obtained, the hinder end being commonly torn 

 away, and concludes that under normal conditions the 

 animal may lose its hinder end but hardly ever loses its 

 head. He thinks that, according to Weismann's views, 

 the animal should accordingly be able to regenerate the 

 hinder end, but not the head end, while his own experi- 

 ments show exactly the contrary to be the case, the anterior 

 extremity being very readily regenerated after amputation, 

 but not the posterior. The author's argument in this re- 

 spect does not appear to us to be very convincing. The 

 facts as stated suggest the possibility that anterior ends 

 are cut off and collected by the dredge because they pro- 

 trude, while the posterior ends remain buried, and that 

 for the same reason the head ends are likely to be bitten 

 off by fishes. If this be so, the fact that the anterior 

 ends and not the posterior are regenerated fits in exactly 

 with Weismann's views. We need to know something 

 definite about the habits of the living animal before coming 

 to a conclusion on this question. It will interest morpho- 

 logists to know that Dawydoff finds in the mode of re- 

 generation of the proboscis pores evidence in favour of 

 Schimkewitsch's view that these organs are homologous 

 NO. 2085, VOL. 81] 



with the " metanephridia " of annelids, consisting each of 

 a mesodermal funnel and an ectodermal canal, the latter 

 of which he regards as of more recent origin than the 

 former. 



Dr. W. F. Purcell contributes to the September 

 number of the Quarterly' Journal of Microscopical Science 

 (vol. liv., part i.) a very interesting memoir on the 

 development and origin of the respiratory organs in 

 .^raneas. He finds that the first " leaves " of the " lung- 

 books " in spiders appear on the free posterior side of the 

 provisional abdominal appendages, quite outside of the 

 pulmonary invagination, and deduces from this fact that 

 the lung-books are derived from gill-books similar to those 

 of Limulus. The tracheal system is supposed to have a 

 two-fold origin, the pair of lateral traches of dipneumonous 

 spiders having been derived from the second pair of lung- 

 books of tetrapneumonous forms, while the medial trunks 

 of the tracheje are equivalent in their entirety to meta- 

 morphosed entapophvses, i.e. to the invaginated ectodermal 

 areas, lined by cuticle, which serve for the attachment of 

 the ventral longitudinal muscles. Dr. Purcell's observa- 

 tions and conclusions should be of great value in settling 

 the much-discussed question of the classification of the 

 .Arthropoda — if it ever is settled. The same number con- 

 tains a further instalment of Mr. Goodrich's work on 

 nephridia, dealing with these organs in Dinophilus and in 

 the larvse of Polygordius, Echiurus, and Phoronis, and 

 some further notes on a trypanosome found in the 

 alimentary tract of Pontobdella muricata, by Miss Muriel 

 Robertson. 



Among the shikar and natural-history notes contributed 

 to the Indian Forester (August) is a note on the Burma 

 mole rat, which, according to the writer, is a serious 

 depredator of Para rubber trees, especially in young 

 plantations, and is also reported to attack seedlings of teak, 

 mango and jack trees. The animal, which is not definitely 

 identified, but may be Nesocia hardwickci, is apparently 

 confined to Burma and western Siam. 



.^N important collation of the genus Cereus and its 

 allies in North America, based upon observations in the 

 field in Mexico and elsewhere, also of living material in 

 the greenhouse in addition to herbarium species, is pre- 

 sented by Prof. N. L. Britton and Dr. J. N. Rose in the 

 final part (No. 10) of the twelfth volume of Contributions 

 from the United States National Herbarium. Following 

 to a considerable extent the revision by Mr. A. Berger, 

 e.xcept that they raise several of his subgenera to generic 

 rank, the authors distinguish twenty-three genera, of which 

 Cephalocereus, Echinocereus, and Lemaireocereus are the 

 chief. The plant originally named Cereus grcggii, that has 

 a curious turnip-shaped root, is made the type of one of 

 the new genera, Peniocereus. The same part contains de- 

 scriptions of five new Mexican Crassulacea> communicated 

 by Mr. J. N. Rose, and a supplement to the monograph 

 of North American UmbelliferiE by Drs. J. M. Coulter 

 and J. N. Rose. 



As might be expected, the officials of the Department 

 of Agriculture in the Federated Malay States have been 

 called upon for advice regarding pests of Para rubber 

 trees. Mr. H. C. Pratt has collected further information 

 on the ravages of the ants identified by him as Termes 

 gestroi, which is published in Bulletin No. 3, together 

 with methods of treatment. No insecticides can be re- 

 commended, but eradication of old tree stumps and care- 

 fully devised fumigation with arsenic and sulphur of the 

 burrows leading to hollow stems have proved efficacious. 

 Mr. W. J. Gallagher discusses in Bulletins Nos. 2 and 6 



