322 SUMMARY OF CURRENT RESEARCHES RELATING TO 



both direct sunlight and darkness. The use of the eye-spot in star- 

 fishes is doubtful. There is a curiously prompt heliotactic reaction in 

 Pentagonaster placenta, from deep water. There is marked negative 

 geotaxis in Aster ina which disappears in foul water, and reappears when 

 this is remedied. The sense is independent of the tip of the arm and 

 of the central body. 



Affinities of Echinoidea.* — Austin Hobart Clark gives reasons for 

 his conclusion that the Crinoids and the Echinoids have much in common. 

 They are much more closely related to each other than either group 

 is to the Asteroids or the Ophiuroids. He proposes the following classi- 

 fication : — 



Phylum — Ecbinodermata. 



I. Subphylum Echinoclermata, Heteroradiata. 



A. Pelmatozoa : Crinoidea, Cystidea, Blastoidea. 



B. Ovozoa : Echinoidea. 



C. Vermiformes : Holothuroidea (Bohadschoidea). 



II. Subphylum Ecbinodermata, Astroradiata. 



A. Ophiobrachiata : Ophiuroidea. 



B. Stellarides : Asteroidea. 



Coelentera. 



Studies on Actinians.f — F. Pax has studied what seems to be 

 Polyparium ambulans, which has been variously interpreted as an 

 Anthozoon colony, a bilateral Actinian, or a fragment of a sea-anemone. 

 Pax regards his specimen as the constricted off oral disk of Stoichactis 

 Jcenti Haddon and Shackleton. 



The author also reports on a collection of sea-anemones made by 

 W. May at Goniera in the Canary Islands. Ten species occur, and there 

 is closest affinity with the Actinian fauna of the Atlantic coast of 

 Europe and the Western Mediterranean. But three species are peculiar 

 to the Canaries — Phellia vestita, Euphellia cincJidifora, and Pa/gthoa 

 canariensis. Pax also describes Bolocera norvegica sp. n. from the west 

 coast of Norway. 



New Species of Cerianthus.J — H. B. Torrey and F. L. Kleeberger 

 describe from Southern California — Cerianthus sestuari sp.n. well marked 

 by the small number of tentacles (never more than 84 of each kind) ; 

 C. benedeni sp. n., resembling externally G. americanus and C. membra- 

 naceus, but differing from these and all other adult Cerianthids, so far 

 as known, in possessing structures like the " botrucnides " (aggregates of 

 cnidoblasts) which van Beneden found in three pelagic Ceriantbid 

 larvae ; and 0. johnsoni sp. n., very closely resembling C. membranaceus, 

 but differing in the arrangement of the mesenteries in the region of the 

 siphonoglyph. 



Rhythm in Sea-anemones.§ — Georges Bohn finds that when the 

 perturbations due to the tides are eliminated, Actinia equina always 



* Arner. Nat., xliii. (1909) pp. 682-6. 



t Jen. Zeitschr. Naturw., xlv. (1909) pp. 325-44 (1 pi. and 3 figs.). 



\ Univ. California Publications (Zool.) vi. (1909) pp. 115-25 (4 figs.). 



§ C.R. Soc. Biol. Paris, lxviii. (1910) pp. 253-5. 



