476 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the egg, i.e. beneficial or injurious, depending upon the duration of the 

 treatment, or in other words upon the condition of the egg when treated. 



In normal fertilization the spermatozoon starts division and at the 

 same time j)revents the production of toxic substances during cleavage 

 or inhil)its their action. It is therefore impossible for the hypertonic 

 sea- water to exercise its protective action upon the normally fertilized 

 egg. It can affect it only injuriously. Moore's experiments show that 

 this injurious action is most pronounced just preceding and during 

 cytoplasmic division, and that such action is very slight immediately 

 afterwards. 



In the case of artificial parthenogenesis the hypertonic treatment is 

 beneficial. According to Loeb the artificial membrane-formation starts 

 the chemical phenomena which give rise to the process of cell-division 

 and development ; but the process is incomplete oi' abnonnal and leads 

 to the disintegration of the egg unless a second treatment is added, 

 usually a treatment with hypertonic sea- water. Since by the membrane 

 formation, chemical or physico-chemical changes induced in the egg 

 are rhythmical, it is intelligible that it should make a difference at 

 which stage of the cycle the treatment with the hypertonic solution is 

 supplied. 



Pacific Holothurians.* — Hiroshi Ohshima reports on a collection 

 made by the ' Albatross ' in the Xorth-western Pacific. It includes 

 forty-six new species, the minute calcareous plates of which are figured. 

 Eleven species are recorded for the first time from the North-western 

 Pacific. The collection contains three new cases of brooding Holo- 

 thurians, Gucumaria ijiniai, C. lamperti, and Tliyone imbricata. In 

 some Holothurians, such as Bathyplotes tizardi, ova are found attached 

 about the mouth in the male. In some deep sea forms the ova are of 

 large size, those of Enypniastes eximia measuring 3-3 '5 mm., and those 

 of Benthodytes gotoi and Euplironides depresm 2 ' 5 mm. in diameter. They 

 exceed the record given by Ludwig for Benthodytes sanguinoUnta 

 (2-2*2 mm.). A peculiarity not uncommon in Elasipoda is the 

 attachment of the third limb of the intestine to the body-wall along the 

 ventral edge of the right dorsal radial muscle. 



Coelentera. 



Hydroid Parasitic on Fishes, f — Ernest Warren describes 

 Hydrichthys boycei which grows on the head, fins, sides, and tail of 

 various fishes — a species of Miigil, AmJjassis natcdensis, and one of the 

 Glyphidodontidffi. It feeds in greater part, if not wholly, on its host. 

 There is a plate-like hydrorhiza bearing elongated hydranths and 

 branching gonostyles. The plate is capal)le of budding medusoids 

 directly without the intervention of any obvious gonostyle. In older 

 colonies one or more somewhat massive vertical outgrowths are formed^ 



* Proc. U.S. Nat. Mu&eum, xlviii. (1915) pp. 213-91 (4 pis.). 



t Annals Durban Museum, i. (1916) pp. 172-87 (4 pis. and 1 fig.). 



