[une 12, 1884] 



NA TURE 



H7 



closely-packed tubes, which overlay the rectal portion of 

 the intestine, and occupied nearly one-third of the general 

 body-cavity. 



On comparing the general structure of this animal with 

 the account given by Mr. Peach, I found that his article 

 dealt so little with anatomical points that it was impossible 

 to say whether or no there was any real relation between 

 his " Cotton-Spinner" and my specimens, which, like his, 

 were of Cornish origin. There was, however, a physio- 

 logical experiment that could be made, and which might, 

 I hoped, be successful. In the description given by our 

 modern master of Holothurian organisation, Semper says, 

 in speaking of the Cuvierian organs : " The sticky property 

 of these organs is known in the true Holothurians, and 

 in England they have even given the name of the 

 ' Cotton-Spinner ' to Holothuria nigra." I attempted to 

 draw out one of the tubes of the mass, and, as I hoped, I 

 found it extend. I threw it into water, and I found that 

 it swelled out. More accurate experiment showed that it 

 could be made to elongate twelve times and to swell out 

 in water to seven times its diameter. It was at once clear 

 that I had before me the creature of whom Peach had 

 written : " It is extremely irritable, and, on being touched 

 or disturbed, throws out a bunch of white tapered threads 

 about an inch in length and one-eighth in thickness.'' 

 Peach goes on to say that they " soon become attenuated, 

 either by the agitation of the water or the coming into 

 contact with something ; " but as he goes on to say that 

 they stick to everything they touch, I doubt not that,, 

 when that thing is alive it tries to run away, till the moral 

 effect of the gradually elongating and as regularly swelling 

 threads paralyses it with fear. At Dr. Giinther's sugges- 

 tion I tested the strength of these elongated threads, and 

 I found that, when so thin as to be barely visible, six were 

 strong enough to hold up a weight of between 800 and 

 1000 grains. 



I communicated a paper detailing the zoological and 

 anatomical characters of this very rare form, which 

 seems to be known only to the fishermen of Cornwall, to 

 the Zoological Society at their meeting on May 20, and I 

 direct attention to it in this more widely circulated journal 

 because it seems to show in a very pointed way how from 

 the absence of opportunity for investigating animals that 

 live not deeper than twenty fathoms we do not only 

 remain ignorant of the contents of our own seas, but that 

 we have in this "Cotton-Spinner" an opportunity of 

 testing' the hypothesis of Semper as to the function of 

 these Cuvierian organs, and of putting on the basis of 

 scientific observation and experiment the "great detesta- 

 tion "in which, as Peach tells us, they are held by the 

 fishermen. While Cuvier regarded the organs to which 

 in later years he was made name-father as testes, and 

 Jager and the great majority of subsequent writers as 

 kidneys, Semper, who had unexampled opportunities of 

 watching and examining them in the Philippines, came to 

 the conclusion that they were organs of offence or defence. 

 To this conclusion the French naturalist Jourdan and the 

 German Dr. Hamann have been led on the ground of 

 histological observation ; in England the only observa- 

 tions yet made have been such as are possible in a 

 museum with specimens that have been in spirit for nearly 

 twenty years. I earnestly hope that the line of investiga- 

 tion indicated by the facts that are here recorded will be 

 soon followed out by one who is working in a marine 

 biological laboratory on the British coast. 



F. Jeffrey Bell 



VISIT A TION OF THE RO YAL OB SER VA TOR Y 



THE visitation of the Royal Observatory, Greenwich, 



-*- took place on Saturday last, when there was a very 



numerous attendance of astronomers and representatives 



of the allied sciences. The Report this year does not 



contain anything striking, but enables us to see how 

 usefully and smoothly the work of the Observatory has 

 been going on during the past year. Still novelties were 

 not entirely absent, chief among them being the new 

 Larsell reflector. 



The new dome for this telescope was completed by 

 Messrs. T. Cooke and Sons at the end of last March, and 

 is in every respect satisfactory. It is thirty feet in dia- 

 meter, covered with papier-mache, on an iron framework, 

 and turns with great ease. The shutter-opening extends 

 from beyond the zenith to the horizon and is closed by a 

 single curved shutter (3 feet 6 inches wide at the zenith 

 and 6 feet wide at the horizon), which turns about a point 

 in the dome-curb opposite to the shutter-opening, and 

 runs on guiding-rails at the horizon and near the zenith, 

 the curved shutter being continued by an open framework 

 to complete the semicircle. This arrangement appears to 

 leave nothing to be desired as regards ease of manipula- 

 tion. After the completion of the dome, the carpenters' 

 work on the flooring, &c, of the building and the attach- 

 ment of the observing-stage (which is fixed to the dome) 

 have necessarily occupied much time, and the building is 

 hardly yet complete in all details. The equatorial has 

 required a number of small repairs and general cleaning, 

 some parts of the mounting having been probably strained 

 in process of removal, and the bearings in particular 

 having suffered from wear and subsequent disuse, so that 

 it has been necessary to raise the instrument and regrind 

 these in several instances. The mirror has been cleaned, 

 and appears to be in very good condition as regards 

 polish. The definition on stars seems to be very good as 

 far as it has been practicable to test it before the mounting 

 of the telescope has been put into proper order. The 

 delay in the completion of the dome has necessarily de- 

 layed the work on the instrument, which is now rapidly 

 advancing to completion. 



First among the astronomical observations properly so 

 called referred to by the Astronomer-Royal was the work 

 done by the transit-circle. " There is no change of import- 

 ance to notice in this instrument, which has been kept in 

 good working order. A reversion-prism for use with the 

 collimators as well as with the transit-circle is being made 

 by Messrs. Troughton and Simms. The sun, moon, 

 planets, and fundamental stars have been regularly ob- 

 served throughout the year, together with other stars from 

 a working catalogue of 2600 stars, comprising all stars 

 down to the sixth magnitude inclusive which have not 

 been observed since 1S60. Considerable progress has 

 been made in obtaining the requisite three observations 

 of each star, and there is a good prospect that by the end 

 of next year, when it is proposed to form a new Nine- 

 Year Catalogue, the whole of the stars will be cleared off. 

 The annual catalogue of stars observed in 18S3 contains 

 about 1550 stars." 



The following statement shows the number of observa- 

 tions with the transit-circle made in the year ending 1884 

 May 20: — 



Transits, the separate limbs being counted as 



separate observations ... ... 5213 



Determinations of collimation error ... ... 303 



Determinations of level error ... ... ... 360 



Circle observations ... ... ... ... 5049 



Determinations of nadir point (included in the 



number of circle-observations).. ... ... 353 



Reflection-observations of stars (similarly in- 

 cluded) 54S 



As regards the computations — 



Clock times of transit over the true 



meridian, corrected for collimation, 



level and azimuth errors, are prepared 



to 1884 May 18 



Clock errors and rates are determined to May II 



Mean R. A.'s for 1884 January I are 



prepared to May 11 



