( 821 ) 

 SUMMAEY 



OF OUEEEKT RESEARCHES RELATING TO 



ZOOLOaY AND BOTANY 



(^principally Tnvertebrata and Cryptogamia), 



MICROSCOPY, &c., 



INCLUDING ORIGINAL COMMUNICATIONS FEOM FELLOWS AND OTHERS." 



ZOOLOGY. 



A. G-ENERAL, including Embryology and Histology 

 of the Vertebrata. 



Development of Muscle-fibres and their TJnion with Nerves.t 

 — Although very numerous researches have been made on the differen- 

 tiation of striped muscles, and on the termination of their motor 

 nerve-fibres, yet the multifarious observations have often been too 

 incomplete to lead to any but conflicting and unsatisfactory theories. 

 An important contribution towards reducing to order this unfortunate 

 and excessive confusion is made by L. Bremer, who has studied the 

 post-embryonic changes in lizards, frogs, and mice. The nucleus of 

 the muscle-fibre, together with the protoplasm surrounding it, consti- 

 tutes the so-called muscle-corpuscle ; the corpuscle is much more 

 prominent in young than in old muscles, for its protoplasm is 

 gradually differentiated into muscular substance ; a small number of 

 corpuscles enter into the formation of each fibre ; the substance of 

 the muscle forms a network, which was first partially recognized by 

 Heitzmann.J The meshes of this network appear polygonal in trans- 

 verse, rectangular in longitudinal sections. The network is a modifi- 

 cation of the protoplasmatic network of the corpuscles, and is so 

 arranged that there are alternating rows, both transverse and longitu- 

 dinal, of fine knots and large knots (corresponding to the fine and 

 broad striae) ; the fine knots are connected by fine threads, and the 

 large knots by coarse threads; hence there is a fine and a coarse 

 net. 



The post-embryonic multiplication of fibres takes place by means 



* The Society are not to be considered responsible for the views of the 

 authors of the papers referred to, nor for the manner in which those views 

 may be expressed, the main object of this part of the Journal being to present a 

 summary of the papers as actually published, so as to provide the Fellows with 

 a guide to the additions made from time to time to the Library. Objections and 

 corrections should therefore, for the most part, be addressed to the authors. 

 (The Society are not intended to be denoted by the editorial " we.") 



t Arch, f. Mikr. Anat., xxii. (1883) p. 318. Abstract by C. S. Minot, 

 Science, ii. (1883) p. 411. 



X SB. Akad. Wiss. Wien, xvii. (1873) Abth. 3. 



