674 ARACHNID A. 



same triDe. Here also appear to belong the genera HersUia, Psamatne, Thyone, and Pcltidium, described by Phi- 

 lippi in Wiegmann's Archives and in the Annals of Nat. Hist, Vol. VI. 



The remarkable Evadne Nordmanni, has been added to the British funna by H. Goodsir, who has given some 

 additional details of it in the thirty-third volume of the Edinburgh Now Philos. Jou: caZ, 



Ai <xjeUent memoir upon the development of the eggs and larvae of Caligus piscinus (p. 447), has dccb pr,ti. 

 lished by H. Goodsir in the thirty-third volume of the Edinburgh New Philos. Journol. 



THE TRILOBITES. (P. 449—450.) 



The question as to the structure, or even of the existence of locomotive organs in the Trilobites, still remains 

 undecided ; although the recent researches of several celebrated comparative anatomists lead to the belief that 

 such organs did exist in the form of thin membranous plates, of which the nearest analogies occur in the genus 

 Branchipus. Dr. Burmeister has especially treated upon this analogy in his fine work upon the Trilobites, of 

 which a Translation has been published by the Ray Society. The relationship of these anomalous animals with 

 other Articulata has also been insisted upon at great length by Dr. Buckland, in his Bridgewater Treatise. If in 

 these respects we have not arrived at definite views, our knowledge of the species has greatly increased ; whilst 

 many new genera have also been defined. The most recent and comprehensive works on these fossil animals, are 

 Dr. Burmeister's volume above referred to, Hawle and Corda's Prodrom einer monographie der Bohmischen Tri- 

 lobiten, 4to. Prague, 1847 ; and Beyrich's Memoir iiber einige Bohmischen Trilobiten, Berlin, 1845. 



A paper on the relations of these animals with other articulata, by Mr. W. S. Mac Leay, may also be re- 

 ferred to. 



ARACHNIDA. (P. 450—471.) 



Since the first edition of this Translation was published, the work of the Baron Walckenaer has been completed 

 in four volumes, forming a most invaluable summary of our knowledge of the Apterous insects (exclusive of the 

 Crustacea), the third volume containing the Phrynidae, Scorpionidae, Solpugidae, Phalangiidce, Acari, Pediculi, 

 Pulicidoe and Thysanura, having been contributed by M. Paul Gervais. The Myriapoda, also described by M. 

 Gervais, occupy half of the fourth volume ; the remainder of which consists of additions to the whole work. As 

 the additions to our knowledge of the Arachnida, consist for the most part of new genera characterized by diversities 

 of structure, without any addition to our knowledge of the economy of the species on which they have been 

 founded, we shall merely refer in this general manner to the sources where they have been described. 



Many curious facts connected with the Natural History of different species of British Spiders, (Araneides 

 p. 454), have been recorded by Mr Blackwall, who communicated an interesting paper on the subject to the 

 British Association of Science, which has since been published in the Annals of Natural History. In one of his 

 papers, published in the eighteenth volume of the Transactions of the Linnaoan Society, he proposes to divide the 

 whole of the Araneides into three primary groups, from the number of eyes — named Octonuculina, eight-eyed ; 

 Senoculina, six-eyed ; and Binoculina, two-eyed. Another paper by he same author, in the nineteenth volume 

 of the same Transactions, contains descriptions of a great number of new British species. 



An important memoir on the Physiology and Natural History of the Araneides, has been published by Menge, 

 in the fourth volume of the Natural History Society of Dantzig. 



The West Indian Mygale nidulans (p. 467), belongs to the genus Actinopus of Perty (Sphodros Walck.) Another 

 closely allied species of trap-door spider was sent from Barbary by Mr. Drummond Hay, which I described in 

 detail in the third volume of the Transactions of the Entomological Society of London. Mr. S. S. Saunders also 

 described a new species of trap-door spider from Ionia, in the same volume, giving a detailed account of its habits 



Mr. A. White, of the British Museum, has also described several new forms of exotic Spiders in the Annals of 

 Natural History ; and Mr. Adams has collected some interesting observations on the economy of various exotic 

 species, which will be published in the zoological portion of the voyage of the Samarang. 



The Scorpionidae (p. 466), have recently formed the subject of a memoir published by M. Gervais, in the fourth 

 volume of the Archives du Museum d' Histoire Naturelle. Eighty species are now known, and which are divided 

 by this author into two groups and eight genera, Androctonus, Centrums, Atreus, Telegoiius, Buthus, Chactas, 

 Scorpius, and Ischnurus. . 



The genus Galeodes (p. 4G7), has been revised by Koch in Wiegmann's Archives, and its species, twenty -nine 

 in number, divided into various sub-genera. Captain Button and Colonel Hearsey have noticed the carnivorous 

 habits of a large Indian species, (Ann. Nat. Hist., 1843.) The anatomy of the genus has been studied by Blan- 

 chard, (Comptes rendus, XXI.) 



Koch (Arachniden X Band.), has described many new species and several new genera of Cheliferides, (p. 467) 

 and Mr. Tulk has noticed a peculiarity in its anatomy, (Ann. Nat. Hist., XIII.) A very remarkable species has 

 been found in the Mammoth Cave in Kentucky, and described by Tellkampf, (Wiegm. Arch , 1844.) 



The Pycnogonida? (p. 468), have been investigated by Krdyer, (Naturhist. Tidsskr., Vol. Ill, and new series, 

 Vol. I), and several new genera and species proposed by Goodsir, (Edinburgh New Philos. Mag., XXXII, and 

 Ann. Nat Hist., XIV and XV). Also by Philippi ( Wiegmann's Arch., 1843), and Quatrefages (Comptes rendus, 

 XIX, and Annales Sci. Nat. third series, Vol. IV), has investigated their internal anatomy, with the view of de- 

 termining their natural position. 



The Phalangita (p. 469), have received many additional new species described by Koch (Arachniden), and 

 Gervais. A remarkable blind species from Guinea, is described by Guerin, (Rev. Zool., 1838.) Mr. Tulk has 



