228 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cell which furnished tho ovary for tho same side. Tho solid mass 

 includes " polyplasts," as in Lumbricus, with non-nucleated blastophorc. 

 These become frco in the coelom, and undergo complete segmentation. 

 Their nuclei form distinct cells (spermatocytes) grouped round the 

 blastophore. They multiply by karyokinesis, after the fashion described 

 by Carnoy as "scission en anscs paralleles," which is very different 

 from Flemming's " hcterotypical form." The spermatides, and the 

 spermatocytes of certain generations, possess an accessory nuclear body 

 ("Nebcnkern"), with filamentous structure, and apparently arising in 

 the nucleus. 



Contrary to Grassi's statement, the sperms havo a distinct head, 

 formed from the nucleus of the spermatide. After the formation of the 

 head, the nuclear caryoplasma seems to be restored to the cytoplasm, the 

 nuclear membrane ceases to be distinct. The sperms have, (1) a pro- 

 cephalic filament, formed by a prolongation of tho cytoplasm of the 

 spermatide, (2) a tail consisting of an axial filament formed in the cyto- 

 plasm of the spermatide, (3) an undulatory membrane, forming a spiral 

 round head and tail, and formed in the cytoplasm. The transverse 

 striation, which has been described, is an optical illusion due to the spiral 

 membrane. 



The spermatozoa occupy in the polyplast a position opposite to that 

 hitherto described in all polyplasts ; the head is turned outwards, and 

 the accessory nuclear body inwards, that is, towards the blastophore. 

 The blastophore, or blastophores — for the primitive blastophore may 

 become multiple by simple segmentation — may be absorbed during the 

 development of the spermatides, or may persist, and be rejected from the 

 polyplast at the end of spermatogenesis. 



Life-history of Gordius.* — Sig. L. Camerano discusses the various 

 species of Gordius found in Italy, and raises several questions in regard 

 to their life-history. (1) Are different species found in distinct hosts ? 

 No, not necessarily. The filiform state is found exclusively in insects. 

 The same species may occur in Arthropods and in fishes. (2) Is man 

 one of the hosts of Gordius ? Probably, in the larval stage. (3) Is the 

 development direct, or is more than one host requisite ? The life-cycle of 

 Gordius is as follows : — (1) Egg, laid freely in water ; (2) embryo, in 

 water, within egg ; (3) larva, (a) free in water for a time, (b) active or 

 passive entrance into a host, (c) encystation ; (4) metamorphosis, 

 probably in the same host, the young stage with a filiform body, buccal 

 aperture, segments and reproductive organs not yet developed ; (5) adult, 

 sexual, free life in water, where copulation and egg-laying occur. 



Development and Specific Determination of Gordii.j — M. A. Villot 

 has another note on this subject in answer to Dr. Camerano, in which he 

 adduces evidence to support his claim to priority as to the methods to 

 be adopted in determining the species of Gordii. He explains that, as 

 the genital organs become developed before chitinization is complete, 

 it is necessary to signify the stage reached by the worm under examina- 

 tion. M. Villot thinks he sees signs of Dr. Camerano not having fully 

 studied his memoirs, and he refuses to accept as distinct certain forms 

 regarded by Dr. Camerano as species, until the latter shall have been 

 diagnosed by the taxonomic laws which he has formulated. 



* Arch. Ital. Biol., ix. (1S87) p. 59. t Zool. Anzeig., xi. (1888) pp. 70-2. 



