420 



Da die hier beschriebene Tänie allem Anschein nach eine neue 

 Species darstellt, so schlage ich vor, sie nach ihrem Fundorte Tac» in 

 punica zu nennen. 



Es sind also zurzeit die folgenden im Darme des Hundes [Ceni is 

 familiaris) lebenden Tänii den- Arten bekannt: Mesocestoides limatuê 

 Goeze, Mesocestoides litteratus Batsch. 3 , Taenia cchinococcus v. Sieb., T. 

 (Dipylidium) cueumerina Bloch, T. marginata Batsch., T. serrata Goeze, 

 T.coenurus Küchenm., T. serialis Baillet, T. krabbei Moniez, T. punicam. 

 Die Mesocestoides- Arten und meine Taenia punica haben einen unbe- 

 waffneten, die übrigen aber einen bewaffneten Scolex. 



St. Petersburg, 10. Juni 1908. 



3. Note on the early Development of a Cladoceran (Holopedium gibberum). 



By W. E. Agar M.A., Zoological Laboratory, Glasgow University. 

 (With 4 figures.) 



eingeg. 15. Juni 1906. 



Material and Methods. 



The specimens were obtained by Dr. W. H. Lang in Loch Arklet, 

 Scotland. They were put straight into formaline when caught. 



Several stains were tried, but only a saturated aquaeous solution 

 of Thionin gave satisfactory results. This stain was almost the only 

 one which gave any differentiation between nucleus and cytoplasm. The 

 chief technical difficulty met with has been the impossibility of orien- 

 tating the eggs and very young embryos. These are practically spherical 

 and at this stage lie without any arrangement in the brood pouch. It 

 thus happened that the greater proportion of eggs and young embryos 

 were cut so obliquely as to be practically useless. As a rule the whole 

 animal was cut with the embryos in position in the brood pouch. The 

 gelatinous cuticle was first removed. 



The following account refers to summer eggs only. 



Development. 



The youngest stage obtained was a segmenting egg of sixteen 

 blastomeres (Fig. 1). The composition of the egg is as follows. In shape 

 it appears a perfect sphere. The egg is large and heavily yolked. There 

 is a conspicious large spherical fat globule, placed slightly eccentrically 

 in the egg. In later stages, when the polarity of the embryo has been 

 defined by the differentiation of the germ layers etc., this fat globule is 

 always found near the ventral surface. The globule is also a conspicious 



;i Diese Species, die meist mit M. lineatus zusammengeworfen wird, halte ich 

 nach meinen eignen Präparaten für sicher verschieden von der voi'igen. 



