SUMMARY OF CURRENT RESEARCHES. 293 



The inheritance in this case was largely maternal as regards the 

 state of the tail, and it will be noted that the number of kittens which 

 were tailless equals that of those with tails, and exceeds it by four if 

 those with rudimentary tails are included. There is a strikingly rapid 

 and cumulative progressive change in the direction of tail-reduction. 



It is, unfortunately, doubtful whether the mother owed her rudi- 

 mentary tail to a germinal variation, or to foetal or post-foetal amputa- 

 tion. Contact with a specimen of the Manx or Japanese race was out 

 of the question. If we did not know the subsequent history, we should 

 conclude in favour of the amputation hypothesis, for the occurrence of 

 reduction of the tail as a true variation is rare in cats. The alleged 

 scar-like end, the two vertebrae (strong enough to be counted as two), 

 the reported strong musculature of the stump, favour the same view, 

 but Kennel does not press the point. The case is interesting enough 

 without forcing it to bear evidence in favour of the possible hereditary 

 transmission of the results of mutilation. For it points to remarkable 

 maternal prepotency, and to a possibly rapid origin of a race like the 

 Manx cats. It gives some support to the view that saltatory or tran- 

 silient variations may be of great evolutionary importance. Prof. 

 Kennel concludes his very interesting paper with a description of the 

 structural differences between a rudimentary tail and the so-called tail- 

 less condition. 



Spermatogenesis in Sparrow. * — G. Loisel, continuing his re- 

 searches on this subject, reaches the following general results. The 

 spermatozoa appear only in spring, and disappear entirely at the end of 

 summer. During the winter, the epithelium of the seminiparous tubes 

 is formed of elements similar to those which occur before sexual maturity 

 in the testis of all Vertebrates. These are primitive germinative cells, 

 and, derived from these, there are oviform spermatogonia. These 

 elements elaborate an internal secretion. On the foundation of this 

 glandular epithelium there is formed, in the spring, the strictly semini- 

 ferous epithelium. At this time the spermatogonia expend their ingesta 

 in successive kineses, thus forming the zone of proliferation, from 

 which arise continually the seminal cells, strictly so-called. The 

 germinative cells continue to secrete, but their cell-bodies, influenced by 

 the multiplication of seminal cells, lose their boundaries, and form a 

 vast nucleated syncytium. Some — the cells of Sertoli, the nutritive 

 •cells, the vegetative cells, &c. — exaggerate the secretory activity seen in 

 winter, and produce a substance which acts with a new intensity, first 

 on the seminal cells, and then on the somatic cells. The others — the 

 reserve spermatogonia, the spore-cells, the indifferent cells, &c. — remain 

 during the summer as a reserve to form the new spermatogonia of the 

 following winter. Loisel's most general conclusion is that in all Verte- 

 brates the 6eminal cells are derived from a glandular epithelium. 



Peculiar Process in Seminal Vesicles of Elk. f — Dr. E. Kolster 

 found that in the seminal vesicles of a specimen of Cervus alces, killed 

 shortly before the commencement of the breeding season, there was a 



* Comptes Eendus, exxxiv. (1902) pp. 853-5; andJourn.de l'Anat. Physiol., 

 xxxviii. (1902) pp. 112-77 (4 pis. and 25 figs.). 



t Arch. Mikr. Anat., Ix. (1902) pp. 100-11 (1 pi.). 



