172 SUMMARY OF CURRENT RESEARCHEB RELATING TO 



the glomus coccygeum in man, and elsewhere. They are built up of a 

 succession of hollow lamellse, each containing a fluid. There is an in- 

 ternal club, also composed of lamellae, surrounding the axis-cylinder. 

 Blood-vessels enter along with the nerves into the corpuscle, l)ut the 

 main part of the internal club remains free. With increasing pressure 

 in the blood-vessels the lamellar spaces expand, and the corpuscles be- 

 come more spherical. The connexion of the corpuscles with the blood- 

 vessels in the mesentery of the cat is very intimate. The details of 

 the structure and relations of the corpuscles are fully discussed. The 

 provisional conclusion reached is that the corpuscles function as re- 

 gulators of blood -pressure. 



Thymus of Axolotl.* — A. P. Dustin contrasts his conclusions with 

 those of Hammar. The small thymic cells, which Hammar interprets 

 as true lymphocytes of mesodermic origin, are regarded by Dustin as 

 of epithelial origin (endodermic or ectodermic according to the origin of 

 the thymus-primordia. The epithelioid cells (ciliated, myoid, cysts, etc.), 

 which Hammar interprets as of ectodermic or endodermic origin, arising 

 at the expense of the primitive reticulum, are regarded by Dustin as of 

 mesodermic origin, at the expense of the intrathymic connective elements 

 (connective, adventitious, perithelia!, etc.). It will be seen that the 

 two views in regard to this mysterious apparatus are radically opposed, 

 which Dustin holds to be a sign of progress. Protesting against the 

 view that the thymus is nothing but a lymphoid organ, Dustin maintains 

 that its only indisputable function is the periodic elaboration — often in 

 immense numbers — of small cells rich in basichromatin. 



Dorsal Shield of Ceratophrys dorsata.t — Martin Boldt has made 

 a careful study of the integumentary ossifications on the back of this 

 Amphibian. He describes the arrangement of the various parts of the 

 shield, its precise position on the back, the structure of the surrouudiug 

 skin, and so on. The shield is for the most part due to an ossification of 

 the internal stratum of the corium and of the subcutaneous connective 

 tissue. 



Classification of Supporting Tissues. |—F. K. Studnicka proposes 

 and expounds an elaborate classification of supporting tissues. 



A. In the first place, there are cellular tissues, either exclusively or 

 predominantly : (1) purely cellular tissue with intercellular bridges— 

 reticular epithelial tissue, neuroglia tissue, notochord tissue, and mesen- 

 chyme tissue, and (2) purely or predominantly compact cellular tissue, 

 i.e. without regular intercellular bridges, viz. vesicular supporting tissue 

 (" diffuse, vesicular supporting tissue of the chordoid type," and so on) 

 and prechondral tissue (" vesicular connective tissue of the chondroid 



type"). 



B. In the second place, there are matrical tissues with true Grund- 

 substanz : (1) gelatinous tissue without or with cells (embryonic meso- 

 stroma, corpus vitreum, medusoid tissue, hyaline tissue of Orthagoriscus 

 bone, and so on) ; (2) lamellar tissue, with or without fibrils ; (3) fibrous 



* Arch. Biol., xxvi. (1911) pp. 557-616 (2 pis.). 



t Zool. Jahrb., xxxii. (1911) pp. 107-34 (1 pi. and 2 figs.). 



X Anat. Anzeig., xxxviii. (1911) pp. 497-513 (1 fig.). 



