ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 705 



Ceylonese Echinoderms.* — W. A. Herdman and Jane B. Herdman 

 report on Echinoids, Asteroids, and Ophiuroids collected off Ceylon, and 

 F. Jeffrey Bell adds some notes. The report includes 28 sea-urchins, 

 24 starfishes, and 14 brittle stars, none of which are new. There are 

 some notes of interest as to distribution, habitat, and variation. 



Regeneration and Syzygy in Comatulidae.f — W. Minckert dis- 

 cusses the meaning of syzygy, the relation of individual colour contrasts 

 to regenerative processes, the regeneration of cirri, disk, pinnules, radii, 

 and arms, and the occurrence of autotomy. The syzygia are regarded 

 as predetermined or preformed areas of breakage, and the hypozygalia as 

 bases of regenerative processes. The syzygia, and probably the modified 

 synarthria between the costals and especially between the first and second 

 brachials, are interpreted as special adaptations in connection with the 

 autotomy which is believed to be of not infrequent occurrence in natural 

 conditions. 



Ceylonese Crinoids.J — H. C. Chadwick gives a full description of 

 Antedon reynaudi, a little known species, and A. okelli sp. n. 



Ccelentera. 



Spermatogenesis of Hydra. § — E. R. Downing finds that the inter- 

 stitial cells are the immediate progenitors of the spermatogonia. They 

 divide by mytosis, filling the space between the ectoderm cells, which 

 elongate peripherally. There is no migration from other parts of inter- 

 stitial cells to the region of testis formation. After repeated division 

 to form the testis mass there comes a time when the daughter-cells 

 formed do not grow to the size of the parent interstitial cell, but remain 

 about half its volume. These cells form the first generation of spermato- 

 gonia. During this division the chromosomes are reduced to half the 

 somatic number and the spermatogonia of the second generation are 

 transformed with little change to spermatocytes of the first order. 

 Mitosis occurs, forming spermatocytes of the second order. These 

 divide indirectly into spermatids which transform to the spermatozoa. 

 The paper contains a detailed account of the histology of division 

 throughout the entire process, a consideration of the mesoderm and of 

 the relation of the bud to the spermary. 



Synonymy of Tubularia larynx. || — A. Fenchel has made an exhaus- 

 tive study of this hydroid, and as a result has been led to slump no 

 fewer than 22 species, existing in the literature under the head of 

 synonyms of Tubularia larynx Ellis and Solander. 



Ceylonese Hydroids.f— Laura R. Thornely reports on 4:3 species 

 collected by W. A. Herdman off Ceylon. Thirteen are new, including 

 Ulavactinia gallensis g. et sp. n., which grows on Gastropod shells. 



* Ceylon Pearl Oyster Report, Iioval Society, Part ii. (1904) pp. 137-50 (2 figs.). 

 + Arch. Natur., lxxi. (1905) pp. 163-244 (1 pi. and 14 tigs.). 

 % Ceylon Pearl Oyster Report, Royal Society, Part ii. (1904) pp. 151-8 (1 pi.). 

 § Zool. Jahrb. Abt. Anat.. xxi. (1905) pp. 379-426 (3 pis.). 

 || Rev. Suisse Zool., xiii. (1905) pp. 507-80 (2 pis.). 



If Ceylon Pearl Oyster Report, Royal Society, Part ii. (1904) pp. 107-26 (3 pis. 

 -and 3 figs.). 



Dec. 20th, 1905 8 * 



