376 SUMMABY OF CURRENT RESEARCHES RELATING TO 



morphological values of a syzygy in the proximal and in the distal 

 portions respectively of the rays and their subdivisions. A fresh 

 mode of formulation is given which it is hoped will be found more 

 elastic, and is based upon seven important generalizations, which are 

 formally stated. He indicates the presence of ten arms only by the 

 number 10 ; assumes that, unless otherwise stated, the first syzygy on 

 the arm is on the third brachial ; if it is on the second, 2 6 is placed in 

 the formula : ^d ov 2p indicates that there are two distichals or two 



palmars, of which the axillary is a syzygy, and -- or ^ that the two 



distichals or palmars are united by a syzygy. Like Bell, he uses B 

 to denote the syzygial union of the two outer radials, and he accepts 

 the proposal for the cirri. 



Coelenterata. 



Origin of the Spermatozoa in Medusae.* — In a short paper on 

 this subject C. Merejkowsky calls attention to the interesting fact that 

 the mature reproduction-follicle of Cassiopea or JRhizostoma bears a 

 close resemblance to the same organ of Pelagia during its very young 

 stages. At a very early stage of development the immature follicles 

 are almost exactly alike in all three genera, but in Cassiopea they 

 undergo very little change. The mature organ is a simple ovoidal 

 pouch, lined with endoderm-cells, and filled with spermatozoa. Accord- 

 ing to the brothers Hertwig, Pelagia passes through a similar stage long 

 before maturity is reached ; but its development in this genus does 

 not stoj) here, and it finally becomes a long, irregular pouch, the 

 tortuous ramifications of which are interlaced in an inextricable 

 tangle. 



It is easy to discern that the simple pouches of Cassiopea open, 

 when mature, into the genital sinus, into which Merejkowsky has seen 

 the ripe spermatozoa escape. He believes that similar openings pro- 

 bably exist in Pelagia ; and he thinks the failure of the Hertwigs to 

 find them is due to the great complexity of the mature follicle in this 

 genus, rather than to the absence of openings. 



The paper also contains a minute illustrated account of the 

 transformation of the endoderm-cells which line the follicle into 

 spermatozoa. 



Endodermal Nervous System in Hydroids.f — Dr. Lendenfeld 

 states that he independently discovered in Australian species of 

 Eudendrium and Campanularia the ring of glandular cells which has 

 been recently described by Weissmann and Jickeli in Eudendrium. 

 He also finds in all the Campauularidae which he has examined a well- 

 developed nerve-ring of endodermal origin, running around the 

 proboscis, just inside the oral opening. In this region a number of 

 sensory cells are found, with stiff hairs, which project among the cilia 



* Arch. Zool. Exper. et Gen., x. (1882) pp. 577-82 (1 pi.). Cf. Science, i. 

 (1883) pp. 287-8. 



t Zool. Auzeig., vi. (1883) pp. 69-71. 



