ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 23 



Raja batis are products of the egg-cleavage. Their number is a 

 definite one, 256 in the male, 512 in the female. As they arise before 

 an embryo, on the unfolding of this latter they have to immigrate intu- 

 it. Only a percentage of them find the way to the normal position, the 

 germinal nidus. The rest, from 10 p.c. to 28 p.c, occupy various 

 abnormal positions, and many of them degenerate in these. Hardly an 

 organ in the vertebrate body is free from possible "infection " by such 

 aberrant germ-cells. In this way one comes to recognise in them the 

 hypothetical "lost germs" of pathologists, but these are entities quite 

 different from anything ever imagined by any pathologist, and, more- 

 over, structures endowed with far more potent attributes for mischief 

 than any " lost germs " ever conceived of by pathologists. 



Such aberrant germ-cells are undoubtedly the seed of those tumours T 

 identified by Wilms as rudimentary embryos or "embryomas." But in 

 mammals the development of such an aberrant germ-cell, or of its pro- 

 ducts, at a later period of life gives rise to something lying in a different 

 portion of the life-cycle, to a pathological asexual generation, or chorion. 

 This is a structure with indefinite unrestricted process of growth, and 

 the tumours generally classed as carcinomatous are of this nature. The 

 problem of cancer is thus a very simple one of embryology. 



Spermatogenesis in Sparrow.* — G. Loisel sums up his researches 

 on this subject. He follows the history of the germinal cells through 

 their successive stages, — spermatogonia, spermatocytes, spermatids, and 

 spermatozoa. The cells of Sertoli are hypertrophied germinal cells, in 

 which the function of internal secretion is dominant. They show three 

 successive phases analogous to the phases in spermatogenesis. Loisel 

 lays particular emphasis on the cytogenic function of the testis (awk- 

 wardly called " morphological secretion ", and the glandular function 

 (chemical secretion) which produces, especially in spring, a fluid con- 

 taining iron, — an excitant to the seminal epithelium. 



Dimorphism of Spermatoaoa.f — Fr. Meves has continued his in- 

 vestigation of this interesting subject. He gives an account of the 

 spermatogenesis in Palvdina, which has normal " hair-like " and peculiar 

 " worm-like " spermatozoa. The former may be called " eupyrene " [cv 

 and Trvprjv = nucleus], and the latter " oligopyrene" for they have little 

 nuclear material. In the case of the Lepidopteron Pygcera, the term 

 " apyrene" is more appropriate for the peculiar type of spermatozoa, 

 corresponding to the oligopyrene type in Paludina. Meves gives an 

 account of the spermatogenesis in both cases. 



We have brought this paper — which deals with a Gasteropod ami an 

 insect — under the general heading " Embryology,'" and we restrict our- 

 selves to noting that the author discusses the dimorphic spermatogenesis, 

 the problem of " reduction," the nomenclature of cell-centres, and the 

 very difficult question as to the possible function of oligopyrene and 

 apyrene spermatozoa. As to the last point, Meves is very cautious, but 

 he is evidently disinclined to regard the forms with little or no nuclear 

 material as functionless. 



* Journ. Anat. Physiol., xxxviii. (1902) pp. 112-77 (4 pis. an<l 11 figs.). 

 t Arch. Mikr. Anat., lxi. (,1902j pp. 1-84 (8 pis. and 30 figs ). 



