October 27, 1892] 



NATURE 



621 



3*98 : its hardness (6*5) is between that of quartz and felspar. 

 It has a perfect cleavage, with a splendent metallic lustre, and an 

 imperfect cleavage nearly at right angles to the former. The peb- 

 bles themselves show no remains of crystal-faces, are bluish-black 

 in colour, and opaque ; but thin cleavage-flakes, when seen in the 

 microscope, have a peculiar purplish red tint, and in convergent 

 polarized light show a uniaxal figure, of which the axis is just 

 outside the field of vision. When digested with hot strong 

 hydrochloric acid the finely powdered mineral is slowly decom- 

 posed, and the titanic acid separates out. In strong hydro- 

 fluoric acid complete solution takes place in a few hours. The 

 mineral is infusible with the blowpipe : fused with microcosmic 

 salt it gives the characteristic reaction of titanic acid, notwith- 

 standing the presence of a small proportion of oxide of iron. 

 Shortly after Mr. Dick's paper had been read, Mr. Baddeley 

 courteously offered to allow me to select a single pebble for the 

 British Museum Collection out of his small store of the mineral, 

 the remaining ones being required by him for sending as sam- 

 ples to be used by searchers in Ceylon. But this store, small 

 though it was, consisted of more than one kind of pebble, the 

 close similarity of aspect being due to friction against a bit of 

 graphite which was with them. On this heterogeneity being 

 pointed out, Mr. Baddeley allowed me to take not only the 

 promised pebble of Geikielite, but also those three pebbles 

 which, not being Geikielite, were useless as samples of that 

 mineral. One of the three fragments proved to be garnet, a 

 second was ilmenite — both of them common minerals — but the 

 third, a fragment of a crystal still retaining some of its faces, 

 presented characters which give it unusual interest. 



The fragment, which weighs just over three grams, is black 

 and opaque, and has the general aspect of columbite ; its ex- 

 tremely high specific gravity (6-02) and its hardness (6-5) are 

 also suggestive of that mineral. In microscopic fragments it 

 transmits light and is dichroic, changing from a greenish yellow 

 to brown with the plane of polarization of the light ; the frag- 

 ments, when examined in convergent polarized light, show a 

 biaxal figure, the apparent axial angle being large (near 70°) ; 

 the character of the double refraction is negative. There is only 

 one well-developed zone of crystal-faces remaining on the 

 fragment ; it consists of two rectangular pairs of parallel faces 

 (pinakoids) and of four prism faces (w), the faces of one pinakoid 

 (fl) being much larger than those of the other {b) ; the angle 

 am, as determined by means of reflection, is about 44°, but the 

 images of the signal are multiple and wanting in definition ; 

 the dispersion of the optic axes indicates that the system of 

 crystallization is mono-symmetric. Two other faces form a re- 

 entrant edge parallel to the larger pinakoid, and inclined to 

 the edges of the well-developed zone, but whether this is really 

 due to twinning or not is far from evident. 



The above set of external characters suggested that the frag 

 ment does not belong to any of the known species, and it became 

 necessary to determine its chemical behaviour, but on account of 

 the necessity of preserving the natural faces of what might 

 possibly be an unique fragment, this was a process demanding 

 great caution ; fortunately, the behaviour was such that it was 

 practicable to determine the precise chemical nature of the 

 mineral without interference with the crystal faces, or, indeed, 

 any appreciable destruction of material. It will be sufficient to 

 state here the result, namely, that the material is no other than 

 crystallized zirconia ; the technical details relative to both this 

 mineral and Geikielite will be given in the next number of the 

 Mineralogical Magazine. It is remarkable that, notwithstanding 

 the wide prevalence of zircon itself (silicate of zirconium), the 

 natural occurrence of the oxide of zirconium has not previously 

 been noticed. For this new species I beg to suggest the name 

 Baddeleyite, in recognition of the services of Mr. Baddeley to 

 mineralogical science ; but for his close scrutiny of the mineral 

 products of Rakwana, the existence of the above remarkable 

 species would doubtless have long remained unknown. 



L. Fletcher. 



NEW BRITISH EARTHWORMS. 

 'T'HE additions which I have been able to make to our list of 

 indigenous Annelids during the past two years fall naturally 

 into two groups. There are, first, two species which are new to 

 science, and are therefore at present known only as British 

 species. In addition to these there are several species which, 

 while they have been recorded for various Continental stations, 



have never been found in England till I discovered them among 

 the gleanings which I have passed under review from nearly 

 every part of the country. I shall first of all give a description 

 of the new species. 



I. Lumbricus rubescens, sp. nov. 



This is a genuine Lumbricus in the strictest sense of the word, 

 as it is understood by all those who adopt Eisen's analysis of 

 this group of worms published in 1873. The lip forms a 

 perfect " mortise and tenon," with the first ring or peristomium, 

 and the girdle consists of six segments, four of which bear the 

 tuberaila pubertatis. I first discovered it in Yorkshire in 1891, 

 and have since then taken it myself at Hornsey in Middlesex, 

 Tunbridge Wells, and Dallington in Sussex, while more recently 

 I have received it from Avonmouth in Gloucestershire. 



In general appearance it resembles the common earthworm 

 (Z.. terrestris, L.), as recently defined and differentiated. It is 

 slightly smaller in size, but frequents similar haunts, and might 

 in most respects easily be mistaken for the type. It has the 

 male pores on segment 15 on raised, pale papillae; but the 

 girdle invariably commences on segment 34, and extends to the 

 39th, while the band which forms the tubercula pubertatis 

 extends over 35 to 38. Its general form and appearance will 



Fig. 1.— Lumbricus rubescens, Friend. Natural size. 



be best understoood by the study of the woodcut (Fig. i). In- 

 ternally it does not differ from the other Lnmbrici, but the 

 dorsal pores commence between J. This makes the fourth true 

 Lumbricus found in the British Isles, and it may be a conveni- 

 ence to collectors if I append a tabular statement of the features 

 by which each is distinguished from the other. 



Chart of the Genus Lumbricus. 



Segments occupied by the 



NO. 1200, VOL. 46] 



j Tuber- 

 1 cula. 



First I 



dorsal Papillae, 

 pore, j 



Terrestris, Linn...! 32 — 37 

 Rubescens, Friend 34—39 

 Rubellus, Hoffm. 27—32 

 Purpureas, Eisen 28—33 



33—36 i S IS, 26 



35—38 ; 8 IS. 28 



28—31 < fr lune 



29—32 j ? 10(11) 



Sperma- 

 tophores 



32/33 



Average 

 length. 



No. of 

 seg- 



5 inches 150 — 200 

 4 inches 1120 — 150 

 3 inches 11 10 — 140 

 2 inches j 100— 120 



It will be seen that there is now a regular series in relation to 

 the first dorsal pore, ^, f , I, §, as well as in the matter of length 

 from 2 to 5 inches and upwards, and number of segments from 

 100 to 200 or thereabouts. These points are worthy of note in 

 the study of the evolution of worms. 



2. Allolobophora cambrica, sp. nov. 



This species, which I have since found in several parts of 

 England, first came to my notice as a new species from Wales. 

 Hence the specific name. I had previously assigned it to one 

 or other of the related species, but eventually found on dissection 

 that it was quite distinct from every other worm of which I have 

 been able to obtain any description. 



At first sight A. cambrica has all the appearance of the mucous 

 worm {A. mucosa. Eisen). Its average length in spirits is about 

 2 inches, but when living, and moderately extended, it measures 

 three inches. It is of a fleshy colour, with a somewhat trans- 

 parent skin, so that the blood-vessels can be well observed 

 between the girdle and the head. The dorsal pores are con- 

 spicuous in specimens which have been placed in methylated 

 spirits, the first occurring between segments 4 and 5. The 



> Vejdoysky and others mention the occurrence of Spcrmatophcres on 

 these species, but do not state the position. The point is one which should 

 not be ignored. 



