ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 29 



Origin of Centrioles of First Cleavage Spindle in Myzostoma.*— 

 K. Kostanecki has made an experimental study of this question in 

 reference to Myzostoma glabrum, and concludes that the centrioles of 

 the first cleavage spindle are certainly derived from the spermatozoon. 



Nematohelminthes. 



Spermatozoa of Ascaris megalocephala.f — L. Scheben finds that 

 the enigmatical refractive body is a not unimportant component of the 

 spermatozoon, which has a role in fertilisation. Peculiar as the whole 

 spermatozoon is, it is deducible from the typical form. 



The author describes the genesis of the spermatozoon from the 

 spermatid, the fully formed spermatozoon, and the apical portion, which 

 has been hitherto overlooked. The general result is that the spermato- 

 zoon is much less divergent than it looks. 



The process of fertilisation is discussed, and an interesting case of 

 polyspermy is reported. Scheben also describes the nutritive-cells and 

 peculiar glandular-cells in the uterus. 



Cutaneous Infection with Ankylostomum.f — Grino Pieri has made 

 experiments which, along with those of other workers, lead him to the 

 following conclusions. Man is infected either by ingestion of the mature 

 larva, Leichtenstern, or by its active penetration through the skin. This 

 applies to Uncinaria americana Pieri as well as to Ankylostomwn duode- 

 nale Looss. The dog is infected (1) when it ingests mature larvae of 

 Dochinius trigonocephalies Leuckart, or of D. stenocephalus Railliet ; (2) 

 when the mature larvae of D. trigonocephalus are deposited on the skin 

 (Looss), or are inoculated hypodermically (Calmette and Breton), or are 

 injected into the peritoneal cavity (Lambinet). Pieri's experiments 

 show that the mature larvae of D. trigonocephalus infect the dog, whether 

 deposited on the skin or injected hypodermically. Penetration through 

 the skin seems to produce more certain and abundant infection than 

 introduction through the mouth. 



Migration, of Trichina Embryos.§— C. Staubli concludes from his 

 observations, which support those of Akanazy, that the embryos pass 

 from the gut into the lymphatic system and thence to the thoracic duct. 

 With the lymph current, helped perhaps by their own movements, the 

 embryos gain the blood-vessels and are passively borne to the muscula- 

 ture, becoming most abundant in muscles which are very active and 

 have an abundant blood supply. 



Platyhelminthes . 



Parasitic Turbellaria.|| — M. Plehn describes, from the blood of 

 carp and tench, two Rhabdoccele Turbellaria about 1 mm. long. One, 

 larger, has pointed hook-like bristles on the edge of the body in a 



* Bull. Internat. Acad. Sci. Cracovie, 1905, pp. 411-16. 



t Zeitschr. wiss. Zool., lxxix. (1905) pp. 397-431 (2 pis. and 3 figs.). 



% Atti R. Accad. Lincei Roma, xiv. (1905) pp. 547-54. 



§ Vierteljahrschr. Nat. Ges. Zurich, 1. (1905) pp. 163-76. 



|| Zool. Anzeig., xxix. (1905) pp. 244-52. 



