302 SUMMARY OF CURRENT RESEARCHES RELATING TO 



TTannn associated with Crinoids of Tropical Reefs.*— F. A. Potte 



has maTe\rMra;1.Ld a study ot the ani.«»J«^|;"^^r:1 

 with the Crinoids of a tropical coral reef, with ebpccial leteieuoe tu 

 c^ltatn T^^^^ Crinoid, Comantkus annulatinn, is remark- 



able for "te extraordinary range of . colour variation from very bgbt- 



coloared individuals (in which white, l^g^^ f ^^^'^f^^ S S 

 minffled in the colour scheme) to others which are entuely daik green 

 m black By far the greater proportion of the associated animals 

 ihitcoC resemblance to th^ Ji-inoids. ^^^^^^^^^ 

 all stages of variation are met with, according to the u^diadua U no^a 

 between a pale form with very narrow stnpes of pigment, to '^^^«f ^^^ . 

 form totally covered with dark pigment. In ,^\'^'''%Z\A^^^^ 

 hand, the individuals associated with even the ^^^ketCi moid possess 

 only nsi-nificant lines of pigment on the otherwise totally ^l^ite body 

 ?n the latter case there i ' then, no protective f -^^ ^^^^^^^^^^^^^ 

 there is perhaps just a hint of its beginning^ ^^f ^fL 'nhi^^ls are 

 Polych^t, an Amphipod, and Ophiomaza (Ophmroid)-the animal, aie 

 dark and occur upon dark-green Crinoids. 



Periproctal Plates of Discoidea cylindrica.t-Frederick J. North 

 descriS the periproct of this exocycloid fossil Echmoid. In most of 

 fossTls of this sort the periproct is represented by an open hole, and 

 little 01 nothing is known of it. la the specimen described the p e- 

 sertt^in?s compete. There are nineteen plates in two cycles of nine, 

 and with an odd pentagonal plate adjacent to the anus. 



Temperature Co-efficient for Segmentation of Arbacia.$-J Loeb 

 and MM Chamberlain have carried out a series ot experiments on 

 Ifbacl-i; a further attempt towards a physico.hemicaexpki^^^^^^^ 

 of certain groups of fluctuating variations. They show that tne 

 Lmpemture co-efficient for the lat^itude of variation of the segmentation 

 of the e- of Arbacia (i.e. the time between the segmentation of the 

 first and last e- of a group fertilized at the same time) is practically 

 ■ fdent'cal whffie temperature co-efficient for segmentation The act 

 isTn tellX on the assumption that the fluctuating variation m this 

 ase f due to a variation \n the mass of enzyme contained m tl^ 

 different eggs, and supposed to be responsible foi the rate ot 

 segmentation. 



Coelentera. 



Remarkable Brackish-water Hydroid.§-James Ritchie describes 



AnmdeUa gemmata g. et sp. n. from a brackish P°2.^ ^^^^f ^^^1^^^";;^^ 

 Lower Beno-al. The generic diagnosis runs:— Polyps solitary ana 

 naked, with conical proboscis, and long, scattered, capitate tentacles 



* Papers Dept. Mar. Biol. Carnegie Inst. Washington, viii. (1915) pp. 73-96 



^' tlnn. MS:^Nat. Hist., xvi. (1915) pp. 499 50^ (^ fig.), 

 t Journ. Exper. Zo.l., xix. (1915) pp. 559-68. 

 I Records Indian Museum, xi. (1915) pp. 541-71 (2 pis.). . 



