146 SCIENCE PROGRESS 



Archives of Internal Medicine of America, 1919, contains a paper by Kofoid, 

 Kornhauser, and Miss Swezy on criterions for distinguishing the various 

 types of entamceba. A table has been provided giving a key which enables 

 one to distinguish between the various types ; this paper has been partly 

 compiled on the work of Dobell, Jepps, Matthews, and Smith. 



The Quarterly Journal of Microscopical Science, Part 4, 1921, contains an 

 interesting paper by Prof. Champy, of Paris, and Mr. Carleton, of Oxford, 

 on the shape of the nucleus : these workers consider that the following 

 factors are responsible for the varying shapes of the nucleus in different cells : 

 (i) Surface tension ; (2) mechanical deformations ; (3) the presence of the 

 Centrosome ; (4) general shape of the cytoplasm ; and finally the presence 

 or absence of various canaliculi and incisions in the nuclear membrane, or 

 of the presence of intranuclear rodlets. 



The Philosophical Transactions of the Royal Society, 1920, contains a 

 paper by Prof. O'Donoghue on the Blood Vascular System of Sphenodon. 

 The author comes to the conclusion that Sphenodon approaches the Lacer- 

 tilia more closely than any other order of the Reptilia, but that it neverthe- 

 less differs from them to such an extent that Giinther was thoroughly 

 justified in placing it in a separate order. 



Prof. Arthur Dendy, of King's College, London, has recently produced a 

 monumental report on the Sigmatotetraxonida collected by H.M.S. Sealark 

 in the Indian Ocean. The scope of the suborder Sigmatotetraxonida is 

 greatly enlarged by the author's inclusion therein of the Lithistidae and 

 Clavulidse, and the group as now constituted is by far the largest of the 

 tetraxonid suborders, being represented in the Sealark collection by no 

 fewer than 125 species. Of this total 57 species are here described as new, 

 6 are identified with previously known species (in some cases as new varieties), 

 and 4 are identified generically only. 



Prof. Dendy has studied the spicules of the Tetraxonida very carefully, 

 and has been able to trace out in a remarkable manner the metamorphosis 

 of various straight, sigmoid, and granular spicules from an original Tetraxo- 

 nida type. It has been shown that a straight spicule occurring in a number 

 of groups of sponges is not necessarily a homologous structure in each group, 

 but in some cases, as in the Tetraxonids, certain straight spicules have been 

 derived from the tetraxonic type by a process of elongation of one axis and 

 the reduction of others. 



The question of the double innervation of striated muscle has come to 

 special prominence within recent years. It is a well-known fact that ordinary 

 skeletal muscle is provided with both sensory and motor nerve-endings. 

 But in addition it has been shown by some workers that what seems to be 

 a third type of nerve-ending can be demonstrated. Some authorities have 

 suggested that this third type of nerve-ending is connected with the sympa- 

 thetic nervous system. In many cases a fine non-medullated fibre can be 

 seen to accompany a medullated fibre, the meduUated fibre being either 

 sensory or motor, the non-medullated fibre being possibly the so-called 

 sympathetic structure. Prof. J. T. Wilson in Brain, 1921, gives a review 

 of the evidence on this subject, and considers that so far no satisfactory 

 proof has been provided of a dual system of innervating motor fibres. With 

 regard to the question of tonus and the sympathetic nervous system, Kuno, 

 working in Starling's laboratory at University College, London, did not find 

 any diminution of tonus after extirpation of the sympathetic or after section 

 of the rami communicantes. Prof. Wilson considers it is difi&cult, if not 

 impossible, to avoid the conclusion that the accessory or tertiary fibres are 

 sympathetic in origin. 



