HARD WICKE 'S S CIENCE - G O SSIF. 



255 



and Oolitic rocks, Crinoids are sometimes very com- 

 mon. This is notably the case in the shales of the 

 Lias about Whitby and at Lyme Regis, where several 

 species of the beautiful Pcntacrinus occur profusely. 

 The heads and the wonderfully complex arms, which 

 must have expanded like a living net when the animals 

 were alive, are preserved in the greatest perfection, 

 and are frequently converted into iron pyrites. The 

 joints of the stems have long been known under the 

 name of "St. Cuthbert's Beads," and as such, Sir 

 Walter Scott alludes to them in his "Marmion." 

 In the Oolite we have such genera as UliUerocriinis 

 and Apiocriniis, the latter perhaps better known as 

 the "Pear Encrinite." In the Bradford clay, near 

 Bath, the thick seam swarms with joints and detached 

 plates of the body, so that the student may here ob- 

 tain material enough to exercise his ingenuity in 

 reconstructing afresh the entire organism. The 

 Apiocrinites were usually fixed to some hard body by 

 means of the base of the column being spread out, 

 something after the way in which such limy sea- 

 weeds as the Corallina officinalis attach themselves to 

 the sea-bed. 



Species of Crinoids belonging to the genus Bour- 

 getocriims (allied to the living Rhizocrinus) occur 

 scantily in the Chalk. In some places in the London 

 clay, as at Witham, in Essex, we get joints of 

 Encrinites allied to the rentacriniies now common in 

 West Indian seas. We have already seen the relation- 

 ship -which the Crinoids bear to the Star-fishes, 

 through such forms as Euryale and Coinatula. In 

 like manner they are related to the Sea-urchins, 

 through such fossil forms as the Saccosoma of the 

 Oolite, and the Marsiipites of the Chalk. To these 

 we shall refer at greater length when we come to treat 

 on fossil Echini. 



MICROSCOPY. 



The late Dr. Henry Lawson. — Many micro- 

 scopists at home and abroad will be saddened to hear 

 of the sudden death, at an early age, of Dr. Henry 

 Lawson, editor of the Monthly Microscopical Journal. 

 He was author and editor of several well-known 

 works, and up to the end of last year was editor of 

 the Popular Science Review. 



Cleaning Spoilt Slides. — In the June number 

 of SciENCE-Gossip'for this year, is a short article on 

 "Cleaning Microscopic Slides," by W. M. Paterson, 

 in which he advises the use of sulphuric acid. Now 

 although I doubt not that his way may be veiy 

 effectual, yet is there not a degree of danger and in- 

 convenience arising from the use of this acid, especi- 

 ally if heated in large quantities ? I therefore pro- 

 pose to give my experience in the following directions, 

 which will I believe, if carried out, insure success 

 to any one who may try it. Using up old slides at 



least saves money if nothing else. In the first place, 

 get a large earthenware pipkin, costing 2jd. (this 

 when bought may seem rather too big, and it will 

 therefore be best to wait till a quantity of slides have 

 accumulated— say five or six dozen), however, the 

 size is of no great consequence. Next, having placed 

 the slides therein, pour in cold water till it rather 

 more than covers them. I say cold, because there 

 can be no danger then of their cracking. Put in a 

 piece of yellow soap about the size of a walnut — 

 though of course the size depends on the quantity of 

 slides. Place this over a fire, — a range is best if it can 

 be had ; it may now be left to boil for three hours, 

 occasionally stirring with a piece of stick, and adding 

 water when necessaiy, i.e. when there is not enough 

 of the soapy solution to cover the slides. They may 

 now be taken off and tipped into another vessel con^ 

 taining warm water, when the slides should be 

 scraped with an old knife, the blade of which should 

 be made soft to prevent scratching the glass. If the 

 first boiling has been sufficient, the balsam will come 

 off almost by" itself, and the varnish, &c., will be 

 greatly loosened. If possible, they should now be 

 put back into the pipkin, clean warm water and 

 soap added, and left to boil for another three or at 

 least two hours ; it will do them no harm, and will 

 more thoroughly cleanse them. Again tip them out, 

 waiting till they have got cooler, when they must be 

 rinsed in clean water two or three times, and wiped 

 quite dry. I have cleaned seven dozen in this way, 

 and have found it answer well. Of course there may 

 be one or two scratched or otherwise spoilt, but 

 could they not be used for opaque objects ? — 

 E. W. IF., Lcwishain. 



Borough of Hackney Microscopical and 

 Natural History Society. — At the last meeting, 

 held October and. Dr. R. C. Kibbler gave a valu- 

 able paper on the ", Anatomy of Insects," the first 

 of a series, beginning with the External Anatomy. 

 It was illustrated with some beautifully executed 

 diagrams. Six new members were balloted for and 

 elected, and five nominations taken. At the last ex- 

 cursion of the Society to Epping Forest, Wood- 

 street Station, I was fortunate enough to secure 

 Plumatella rcpcns. I am informed that it has never 

 been taken there before. — Collis WillmoU. 



A One-armed Hydroid. — M. Mereschkowksy 

 has described a remarkable form of polyp found in 

 the White Sea, adhering to the shell of Tellina 

 solidula, and which is remarkable for the extra- 

 ordinary length of its single tentacle. He has called 

 it by the generic name of Monobrachiu7n, 



Raphides. — " E. W. W., Lewisham," willfind.the 

 following a good plan for mounting plant crystals 

 ill situ, and he will at the same time be able to ob- 

 tain the tissues in a transparent state. If the object 

 to be mounted should contain cJilorophyll, such as a 



