458 SUMMARY OF CURRENT RESEARCHES RELATING TO 



material) are amplified. Nineteen of the species discussed are restricted 

 to the west coast of North America, the remainder being cosmopolitan or 

 circumpolar. Attention is directed to the relationship existing between 

 a Cyphonautes-larva frequently met with, and Membranipora villosa 

 Hincks, a species rather abundant on the Pacific coast. 



Rotatoria. 



Rotifers from Gough Island.* — James Murray reports that a small 

 tuft of moss brought from Gough Island by the 'Scotia' expedition 

 harboured Philodina flaviceps Bryce, Callidina angusticoUis Murray, and 

 a Bdelloid egg. 



Echinoderma. 



Luminosity of Ophiuroids.f — E. Trojan has studied the luminosity 

 of Ophiopsila aranea, 0. annulosa, and Ophiocaniha spinulosa. It in- 

 creases with stimulation, is not separable from the animal, has not to do 

 with exuded mucus, and is entirely intracellular. The seat of the 

 luminosity is in some of the epidermic cells. 



Observations on Ophiopsila4 — A. Reichensperger finds that the 

 brittle-stars of this name have an epithelium which is able to form 

 strong " cilia " at various parts of the surface, e.g. on the " ciliated 

 spines " beside the internal " tentacular scale." The rows of " cilia " 

 keep currents going over the disk, and thus help in nutrition and 

 respiration. The " cilia " are really comparable to the " combs " of 

 Ctenophores ; they arise from a cell-complex by the fusion of many 

 individual cilia. The " ciliated spines " are movable by a muscle, and 

 are transitional between lateral spines and tentacular scales. In 0. 

 annulosa there are usually twelve pores on the Madrepore plate ; in 

 0. aranea there are very few (1 to tf) ; both species have five Polian 

 vesicles, instead of four, as in the other five-rayed Ophiuroids that have 

 been studied ; the water-vascular system forms a close whole. The 

 tentacles have a strongly differentiated sensory epithelium ; in the distal 

 parts of the arms they bear sensory buds. 



Japanese and East Indian Echinoderms.§ — H. L. Clark gives an 

 annotated list of 70 species, including new species of Pteraster (2), 

 Asterias (1), Ophiozona (1), Ophioglypha (1), Ophiocreas (1), Spa- 

 tangus (1), and Molpadia (1). Except in the case of Asterias, a list of 

 the known species is given, and a diagnostic key of great service. 



Coelentera. 



Species of Hydra. || — W. Weltner discusses the distinctions between 

 the German species of Hydra. It seems that H. viridis, H. grisea, and 

 H.fusca may be distinguished by their colour, form, length of tentacles, 



* Proc. Roy. Phys. Soc. Edinburgh, xvii. (1908) pp. 127-9. 

 + Biol. Centralbl. xxviii. (1908) pp. 343-52. 



\ Zeitschr. Wiss. Zool., lxxxix. (1908) pp. 173-92 (1 pi., 3 figs.). 

 § Bull. Mus. Comp. Zool. Harvard, li. (1908) pp. 279-311. 

 || Arch. Natur., lxxiii. (1907) pp. 474-8 (1 fig.). 



