ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 499 



chromosomes during the whole growth-period of the oocytes ; (*2) the 

 increase in length and the branching of the chromosomes as the oocytes 

 increase in size, and the very great reduction in the size of the chromo- 

 somes as the oocytes ripen ; (3) the casting out from the nucleus of a 

 large number of what appear to be chromatin-granules, at about the 

 time when the spermatozoon enters the accessory cells ; and (4) the con- 

 nection of each oocyte with two accessory cells, within which is developed 

 a definite path for the spermatozoon from the sperm-duct to the ovum. 

 The spermatogenesis is partially described, and the differences between 

 the author's observations and those of Lee are indicated. The most 

 striking elements among the sperm-cells of Sagitta are the cells of the 

 growth-period preceding the two maturation divisions, where the 

 chromosomes appear as nine large, very regular crenate loops. 



Nematohelminth.es. 



Sense-Organs of Ascaris.* — R. Goldschmidt has made an elaborate 

 study of the sensory structures in Ascaris lumbricoides and A. megalo- 

 cephala. ■ These fall into three groups, — the lip-organs, the neck-papilla;, 

 and the anal papilla; . He shows that there is much that is peculiar in 

 the relations between the sensory nerves, the supporting cells, and the 

 conducting cells. As to the functions of the organs we are left almost 

 to supposition. In cases where the organs end beneath the thick cuticle 

 it is very difficult to suggest a function. 



Platyhelminthes. 



Marine Parasites in Fresh-water Fishes.f — F. Zschokke has an 

 interesting essay on the occurrence of marine parasites on fresh-water 

 fishes. Thus forms like Ascaris clavata, Echinorhynchus acus, Distomum 

 varicum and D. appmdicidatwm, which are to be regarded as distinctly 

 marine, occur occasionally in fresh-water fishes. A good case is the 

 occurrence of Scolex polymorphus in Cottus gobio. The author discusses 

 the 31 parasites of Lota vulgaris and the 15 of Silurus glands, and shows 

 how they occur in other hosts — fresh-water, marine, and migratory 

 fishes. 



New Case of Dipylidium caninum in Man.J — F. Zschokke reports 

 another case of the occurrence of this tapeworm of cat and dog (= Tamia 

 cucumerina, T. elliptica, &c.) in man. About three dozen cases have 

 been recorded, usually in children, except in Switzerland where four of 

 the sis cases were adults. The larval stage occurs in the Trichodectes 

 canis (Melnikoff), Pidex serratus, and P. irritans (Grassi and Eovelli), 

 whence it passes to dog, cat, or man. .Prof. M. Braun adds a note of 

 another case from a child in the London Hospital Medical College. 



Drepanidotaenia tenuirostris.§ — T. B. Rosseter describes this tape- 

 worm, in regard to which there has been a good deal of vagueness. He 

 obtained it by infecting domestic ducks with cysticercoids, the origin of 



* Zool. Jahrb., xviii. (1903) pp. 1-57 (5 pis.). 



t Verh. Nat. Ges. Basel, xvi. (1908) pp. 118-57 (1 pi.)- 



j Centralbl. Bakt. Parasitenkunde, 1" Abt., xxxiv. (1903) pp. 42-3. 



§ Jouru. Quekett Micr. Club, 1903, pp. 399-406 (1 pi.). 



