September i6, 1897] 



NATURE 



469 



Reference to Dr. Murray's well-known figure of the coccoliths 

 gathered from the surface waters of the North Atlantic, at once 

 shows the close resemblance of both bodies. In a certain focal 

 plane, indeed, the resemblance is even still more striking. Dr. 

 Murray's drawing is reproduced in Mr. G. Murray's and Mr. 

 Blackman's article appearing in Nature, April i, 1897, p. 510. 

 It is of interest to note that Biilschli records the appearance of 

 disc-shaped plates of uncertain origin in Diffiugia. 



The number of Difflngia present in our slides is very con- 

 siderable, and of this number perhaps some 25 per cent, show 

 one or two implanted coccoliths. Furthermore, the Dijftugia 

 are by no means confined to the immediate surface. Sinking 

 our dredge to a depth of eight fathoms in Killiney Bay, we still 

 obtained this organism ; and varying states of wind and tide 

 did not appear to affect its numbers. 



The first question that arises is as to the relation which the 

 minute adherent organisms Ijear to the Difflngia which carry 

 them. The surmise naturally arrived at was that the relation- 

 ship is accidental. The protozoan gathers its covering particles 

 from such minute hard bodies as it finds convenient ; am )ng 

 them it occasionally picks up an organised particle — the coccolith. 

 If this surmise as to the relations of the two organisms is 

 correct, it must follow that examination of the most minute solid 

 constituents of the sea water will reveal the presence of free 

 coccoliths in considerable numbers. To test this question, some 

 two litres of sea-water was permitted to stand twenty-four hours 

 in a tall narrow jar ; the upper part being then syphoned off, 

 leaving some 2CX) c.c. of the lower portion. This was then 

 treated in a centrifugal apparatus, readily fitted on a small 

 dynamo, permitting a high rate of rotation. In this manner the 

 water was cleared in a very short time of all turbidity, and a 

 mat composed of its solid contents thrown to the bottom of the 

 tubes of the centrifuge. ^ 



Examination of this precipitated material showed at once that 

 coccoliths in a free state abounded in the water, every slide 

 showing not less than a few score of specimens. Fully provided 

 with specimens thus favourably placed for observation, we were 

 enabled to confirm our previous observations as to the structure 

 and probable composition of these bodies. 



As full details are hardly in place here, we will refer at once 

 to Fig. 2 for perspective appearances of the organism. The 

 figures are more in outline than 

 our original drawings, to permit 

 of more ready reproduction in 

 these pages. Figs, a and b are 

 perspective views of opposite faces 

 of the valves. Fig. c is an edge 

 view. We explain the appear- 

 ances presented in these drawings 

 with considerable confidence by 

 the diametral section shown in 

 Fig. d. The coccolith consists of 

 two very thin, funnel-shaped, 

 elliptical valves ; a small valve 

 attached by a central connec- 

 tion within a wider, and pro- 

 vided with minute radial striations 

 sculptured apparently on the outer 

 or convex surfaces of both valves ; 

 Ijetween forty and fifty striations 

 going round the valves. The 

 connection attaching the valves is 

 rounded or slightly oval and 

 apparently perforated axially by \ 

 two D-shaped apertures, but oc- ! 

 casionally a single oval opening 

 traverses the collar ; or, again, the cross-piece separating ; 

 the D-openings appears incomplete, and is represented by pro- \ 

 jections extending into an oval opening. "The more minute , 

 structure of the connecting neck or attachment is unknown to ' 

 us. The valves are frequently found chipped and fractured, but, ! 

 so far as observed, always rigidly connected one with another. 

 Specimens considerably less in dimensions than the normal are 

 occasionally found, but identical in form. The resemblance 

 between our drawings and those given by Biitschli in his 

 Protozoa (Plate i, Figs. 2-5) at once confirms the view that 

 these organisms are identical with those described by this 

 authority as " Coccolithen." The organism is a most difficult 

 and illusive object owing to its minuteness, transparency and 

 1 Later we netted them on silk in abundance. 



Fig. 2.— Coccolith 

 diams. q.p. 



i complex structure. Our drawings are made with a 1/12 oil 

 j immersion of Leitz. 



The coccoliths dissolve freely in dilute hydrochloric acid, and 

 , are partially and much more slowly attacked by strong caustic 

 potash. The latter reagent does not appear to be able to com- 

 pletely dissolve the central parts, more especially of the lesser 

 valve ; or at least cannot do so with any celerity. The absence 

 of the appearance of free gas upon attack with the acid hardly 

 negatives the idea — agreeable with the observations of Dr. 

 Murray and others— that these bodies are calcareous. In all 

 these tests we have frequently had well-characterised diatoms 

 present in the same field, and whereas the characteristic 

 silicious covering of the latter held out against the acid, the 

 coccolith immediately dissolved. In the application of the 

 caustic potash test diatom valves were also present, and these 

 showed complete resistance to the caustic alkali. 



That there is some living matter present between the valves 

 appears suggested by the granular appearance often presented 

 in the ring embracing the central connection, and also by the 

 fact that upon solution in dilute acid just such a ring of granular 

 particles is thrown down, and alone remains to mark the spot 

 where the coccolith had been. This granular remains assumes 

 a tawny yellow or brownish colour when acted on by iodine. 

 The inference is that a ring of (residual ?) protoplasmic matter 

 surrounds the central connection of the valves. Neither 

 nucleus, flagellum, pseudopodia, nor cilia have as yet been 

 observed, neither have we found any evident chromatophores. 



In the present stage of our inquiry we can only ask with 

 considerable uncertainty as to the nature and affinities of this 

 interesting organism. Its rigidly attached valves, absence of 

 girdle, and the calcareous nature of the valves, negative, we 

 think, the idea that it is — as sometimes assumed — of diato- 

 maceous nature. Its relationship with the Foraminifera is more 

 probably suggested. 



The possibility that they are commensal with, or parisitic 

 on, the protozoan which so often carries them, must not be for- 

 gotten ; at the same time our abundant free specimens appear 

 so often ringed between the valves with proteid matter, that their 

 independent existence appears highly probable. There is at 

 present hardly data sufficient to render them referable with 

 certainty to either one or the other kingdom of organised beings. 



It may be assumed that they are abundant in our coastal 

 waters as well as in the open ocean, where they in certain places 

 bear a part in the formation of the Atlantic ooze. These cir- 

 cumstances, as well as their geological importance, confer great 

 interest on the problem of their life-history — a problem the 

 solution of which we do not think need be despaired of where 

 such abundant materials are at hand. J. JOLY. 



Dalkey, August 27. H. H. Dixon. 



P.S. — Since the above was written we have found a few 

 coccospheres in the water off this coast. These appear very 

 scarce compared with the abundance of coccoliths. The 

 abundance of the latter is remarkable. A sample of water taken 

 some three miles from the shore on a calm day afforded, accord- 

 ing to an estimate made with a divided stage, 200 coccoliths in 

 each cubic centimetre of the sea-water ! If this abundance 

 obtains at other points along our coasts (we hope shortly to have 

 results bearing upon this question), they must be one of the most 

 abundant organic constituents of our seas. 



We have found many specimens of the free coccoliths with a 

 slimy proteid (?) attachment to the smaller valve. 



Between crossed nicols the thin flange of the larger valve 

 appears inactive ; the entire inner ellipse, on the other hand, 

 shows a dark-cross, the arms in some cases revealing a certain 

 amount of spiral bending. A concentric and crystalline structure 

 is thus suggested. J. J. 



September 9. H. H. D. 



A Bright Meteor. 



On Monday evening, the 6th inst., at 7.49 p.m. (Dublin 

 time), I was walking from Blackrock to Dublin on the 

 Black rock road, and when passing by Booterstown I saw a 

 very fine meteor of a brilliant white (such as the magnesium 

 light) pass across the sky under the Plough at a slow rate, the 

 course being parallel to the two lower stars of the four forming 

 the Plough, and about the distance between the two "pointers ' 

 under it. It covered a flight of about 10° to 12°, and dis- 

 appeired at a point about 15" to 20° abave the horizon 



Dablin, September 9. 



J. P. O'Reilly. 



NO. 1455, VOL. 50] 



