492 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The phenomena agree with those already recorded in the case of some 

 lichen-gonids. 



Reproduction of Chlorocystis.* — According to Mr. G. T. Moore, 

 Chlorocysti8 Gohnii, a unicellular alga growing on Enter omorpha, is not 

 always an endophyte, but as often merely an epiphyte. The chromato- 

 phores vary from a unilateral arrangement to a complete lining of the 

 wall of the cell. The zoospores are of two different sizes, but they 

 do not appear to conjugate. They are discharged through a circular 

 opening, not through a tubular neck. 



Caulerpa.f — Herr J. Eeinke publishes a monograph of this very 

 sharply differentiated genus of Multinucleate. Thirty-seven species are 

 described, but without definite diagnoses. They are arranged in nine 

 groups, viz. those of C. verticillata, prolifera, taxifolia, Harveyi, cupres- 

 soides, racemosa, papillosa, Fergusonii, and hypnoides, and he regards 

 G. fastigiata as the ancestral form. 



The morphology of the genus is then described in detail under the 

 following heads : — General structure ; the rhizome ; the roots ; the 

 assimilating organs ; the growing point ; the internal differentiation 

 (beams and fibres) ; adaptation to environment ; propagation. In many 

 species the growing point has not as yet been observed ; where it has 

 been, the appearance of the apex recalls that of Cormophytes. The 

 author thinks it probable that all the Caulerpeae have become aposporous, 

 and that discovery of swarmspores is not to be expected. He regards 

 Gaulerpa as a true unicellular multinucleate structure. 



Coccospheres and Coccoliths. — From material obtained from the 

 West of Ireland (Goccosphsera pelagica), Dr. H. H. Dixon J draws the 

 following general conclusions : — The body of the coccolith extends for 

 a short distance inside the internal valve. The coccolith is composed of 

 calcium carbonate, and a trace of some substance soluble in a 1 per cent, 

 solution of sodium carbonate. Coccospheres are covered over with an 

 extremely delicate pellicle, which is less readily soluble in dilute acids 

 than the coccoliths within it. The coccoliths on a coccosphere are 

 partially imbedded in a slimy proteid material. Within the slimy layer 

 there is a somewhat stratifisd internal spherical membrane. The speci- 

 mens of coccospheres examined contained no chromatophore. In many 

 instances the presence of a minute internal body, presumably a nucleus, 

 was demonstrated. Coccoliths are secreted internally in close proximity 

 to the nucleus ; the collar uniting the valves is first formed, then the 

 valves are developed, and finally the central body of the coccolith is 

 secreted. The coccolith, when complete, is probably extruded to the 

 surface, and takes up its position among its predecessors ; its valves 

 become interlocked with those of its neighbours. By this intercalation 

 an increase in the volume of the sphere is provided for. The oval and 

 disk-like form of the coccoliths are adaptations to allow of the rearrange- 

 ment of the older coccoliths on the extrusion of a new one, and of suitable 

 interlocking on the spherical surface. 



* Bot. Gazette, xxix. (1900) p. 138. 



f Wiss. Meeresunters. ; herausgeg. y. d. Commission z. Unters. d. deutschen 

 Meere, v., Heft 1, 98 pp. and 87 figs, 1899. See Bot. Centralbl., lxxxii. (1899) p. 110. 

 Cf. this Journal, 1899, p. 62. 



X Proc. Roy. Soc, lxvi. (1900) pp. 305-15 (1 pi.). Cf. this Journal, ante, p. 406. 



