RECENT ADVANCES IN SCIENCE 57 



of the Family Chermesidse : No. 1 , The Biology of the Chermes 

 of Spruce and Larch and their Relation to Forestry," by 

 Steven (Proc. Roy. Soc. Edin. Dec. 191 7) ; " A Note on the Cole- 

 opterous Genus Euxestus," by Arrow {Ann. and Mag. Nat. Hist. 

 Nov. 1917); "The Homoptera of Indo-China," by Distant 

 (ibid. Oct. 191 7) ; " Records of some British Symphyla," by 

 Bagnall (ibid. Nov. 1917) ; " Notes on Fossorial Hymenoptera : 

 XXIX. On new Ethiopian Species " (ibid. Oct. 191 7) ; " Notes 

 on Fossorial Hymenoptera: XXXI. On Psammocharidse in 

 the British Museum " (ibid. Nov. 1917), and " Notes on Fossorial 

 Hymenoptera : XXX. On new Ethiopian Scoliidae " (ibid.), all 

 by Turner ; " Descriptions and Records of Bees, LXXVII " 

 (ibid. Oct. 191 7), and " Descriptions and Records of Bees, 

 LXXVIII " (ibid. Dec. 1917). 



Papers on Echinoderms include : " British Fossil Crinoids : 

 XI. Balanocrinus of the London Clay," by Bather (Ann. and 

 Mag. Nat. Hist. Dec. 191 7) ; " New Genera and Species of 

 Brisingidce," by Fisher (ibid.) ; and " The Early Development 

 of a Starfish, Pateria (Asterina) nuneata," by Heath (Journ. 

 of Morph. vol. xxix. Sept. 191 7). 



In a paper " The Cytoplasmic Inclusions of the Germ-Cells : 

 II. Helix aspersa," by J. Bronte" Gatenby (Quart. Journ. Micro. 

 Set. vol. lxii. Dec. 191 7), this author continues his observations 

 on those constituents of the cytoplasm of the germ-cell that 

 are usually overlooked when ordinary fixatives are employed, 

 but which nevertheless from their behaviour appear to be 

 structures of considerable importance. Two different sized 

 bodies are to be found in the cytoplasm, the larger macro- 

 mitochondria and the smaller micromitochondria, the latter 

 appearing in the early spermatid and form the front sheath 

 of the sperm. The behaviour of the " Nebenkern " is described 

 and its probable function discussed. Not merely are these 

 bodies described but details are added to our knowledge of the 

 derivation of the sperms, eggs, and nurse cells. From appar- 

 ently indifferent cells in the hermaphrodite gland of the snail, 

 either sperms or ova can be produced, but the determining 

 factor is by no means clear — it does not appear to be the 

 proximity of yolk cells as has been suggested by certain authors. 



Vertebrata. — " Proboscis Pores in Craniate Vertebrates, a 

 Suggestion concerning the Premandibular Somites and Hypo- 

 physis," by Goodrich (Quart. Journ. Micro. Sci. vol. lxii. 191 7) 



