"1">0 SI M.MARY OF CURRENT RESEARCHES RELATING TO 



if anything, has been taken away, and, especially, what is now being 

 reconsidered. An endeavour — necessarily straitened by the limits of 

 the short course of lectures — was also made to suggest how Darwinism 

 touches everyday life, in farm and garden, in city and empire. 



Development of Wolffian and Mullerian Ducts in Rodents.* — 

 ( iasimir Kwietniewski has studied this in guinea-pig and rabbit. In the 

 former the seminal vesicles arise as conical evaginations of the Wolffian 

 ducts ; the Wolffian and Mullerian ducts open at first separately on the 

 colliculus seminalis ; by an insinking on the colliculus seminalis the 

 Mullerian ducts are drawn into the depression, and the caudal portions 

 of the Wolffian ducts are brought close together ; the epithelial partition 

 disappears and the lumen of the united Wolffian ducts coalesces with the 

 caudal ends of the Mullerian ducts ; the Mullerian ducts remain as the 

 uterus masculinus. In the rabbit the Mullerian ducts are displaced 

 ventrally by the parts of the Wolffian ducts which coalesce to form 

 "Weber's organ," and take no part in forming this organ. 



Development of Bone and Dentine.f — J. Disse discusses the forma- 

 tion of the amorphous ground-substance by the protoplasm of the cells 

 and the differentiation of fibrils within this. These fibrils appear after 

 the ground-substance is separated from the cells, and are quite indepen- 

 dent of the cells which form the fibrils. 



Involution of Thymus in Rabbit.J — <>• Soderlund and A. Backmann 

 supply precise facts in regard to the changes in the thymus as age in- 

 creases. When preparations for spermatogenesis begin, i.e. at an age 

 of four months, the weight of the thymus as a whole and of the two 

 parts of the parenchyma (medulla and cortex) reaches a maximum total 

 of 2*49 grm. A rapid decrease sets in. marked especially by the reduc- 

 tion of the cortex. 



Development of Lymphatic Ganglia in Mammals. §— J. Jolly and 

 A. Carran have studied the development of the popliteal ganglion in 

 sheep embryos. The first stage is a group of anastomosing lymphatic 

 vessels ; the connective tissue between is modified into a primitive nodule, 

 a cellular reticulum ; the third stage is marked by the penetration of 

 blood-vessels and the beginning of lymphoid infiltration. At this time 

 the lymph current surrounds the primitive nodule ; the penetration of 

 the nodule by the marginal sinus is later. The cortical lymphoid layer, 

 traversed by the sinus, forms both the cortical and the medullary 

 substance. 



Development of Auditory Ossicles in Horse. || — Ray F. Coyle finds 

 that the malleus, incus, and stapes are derivatives of the mandibular 

 arch. The stapes and incus are at all times structures distinct from the 

 Meckelian bar, being chondrified independently. The malleus on the 

 other hand is continuous with the proximal end of Meckel's cartilage. 



* Anat. Anzeig., xxxv. (1909) pp. 240-56 (13 figs.). 



t Arch. Mikr. Anat., lxxiii. (1909) pp. 563-606 (2 pis.). 



X Tom. cit., pp. 699-725 (1 pi. and 6 figs.). 



§ O.K. Soc. Biol. Paris, lxvii. (1909) pp. 640-3. 



|| Proc. R. Soc. Edinburgh, xxix. (1909) pp. 582-601 (6 pis.). 



