SC /fiNCE-GOSS/J'. 



■43 



inalrix til' rublily, chalky cluy, uiulvr wlucli is a 

 rDnluied mass iif pieces of harduiicd Cliiilk. These 

 |)ieees are said \i\ Mr. VV. Whilaker, K. U.S., K.(j.S., 

 to lie us hard as most crystalline limeslniies. The 

 same fiinnation has been miticcd in other places in 

 the nei(;hlMiurhoo<l. The Chalk seems to have hcen 

 liroken up, and rcdepositcil before the deposition of 

 the overlying Ke.idiny Heds. .\ similar lied has been 

 mil wiih between Uradtield and ranj;lioiirn ; mar 

 I'ilclmrsi, and also near Maidenhead. The raised 

 beach al Kemp Town, Hrij^hton has recently evhihited 

 a similar bed in its eastern part, ovvin^; to falls of 

 clitV. It lies between two beds of rolled beach. 



The following are some measurements of the 

 depths, in feet, at which the surface of the Chalk was 

 found beneath the .south side of London, each list re- 

 presenting a different direction. 

 I. 



Morllake, 315. 



Kingston-on-Thames, 412. 



Richmond (Star and Garter), 416. 



I'"sher, 360. 



II. 



\ aushall, 224. 



Wandsworth lirewery, 274. 



Wandsworth Prison, 357. 



.\litcham, 1S9. 



New Wimbledon, 193I. 



Wimbledon Common, 465. 



Wimbledon (Hospital), 567. 

 III. 



Cuys Hospital, 197. 



Soulhwark, 203. 



Stamford Street, 210. 



Charing Cro.ss Bridge, S., 245. 



Stockwell Green, 2!o. 



l.ambeth. South Lambeth Road, iS". 



Champion Hill, 2 to. 



.Streatham, 241.'.. 



IV. 



Rolherhithe, 66. 



Horselydown, 158. 



Forest Mill, 300. 



I'rom this it will be noticed that the Chalk ri.ses 

 nearest the surface in the southeastern corner of the 

 London area, and is represented in List I\'. as reach- 

 ing svithin 66ft. of the surface at Rotherhithe, but 

 there is a thickening of the overlying beds in a 

 westerly direction. The Chalk is, indeed, exposed 

 in the i|uarriesat Loampit Hill, Lewishani. 

 (To /■(■ conliniti'd.) 



I'livsi. At, .\l'i'AK.\TUs. — Mr. T. M. F. Tandyn- 

 Watts, .V.M.I.E.L., of Goldielands, Settle, \o\V 

 shire, has favoured us witli his catalogues of physical 

 and electrical apparatus respectively. The former 

 contains S80 items. They are both illustrated, and 

 appear li> include the most useful electrical apparatus 

 for laboratory and sturlent's use. \'nrious materials 

 are included, such as ebonite, vulcanized fibre, metals 

 etc., together with different wires. There is likewise 

 an improved form of tangent galvanometer and 

 m.agnelometer. Both catalogties are furnished with 

 an index. 



I..\K\.\I. ()]■ I .\1'KI.I.L.\. 

 f\y the many curious forms of animal life to lie found 

 ^-^ on the sea shore, there are few that for groles<iiie- 

 ness of form surp.iss the crustaceiin popularly known 

 ;ls the skeleton shrimp (Capnlla). The most casual 

 glance will a-ssure the observer that the term has Iwen 

 well applied, for the body closely resembles the 

 vertebral column of an animal, the pouch of the female 

 bearing no small likeness to the bony framework of 

 the chest. The hooks of the second pair of legs in 

 the male are developed into enormous claw.s, or 

 claspers, which are not unlike a man's clenched fist. 



The Ca/inlla belongs to the .subclii.ss Loemodiixida, 

 a division of the sessile-eyed Cnistaccae. The animals 

 have seven pairs of hooked feet, but in this genus the 

 third and fourth pairs are aborted, their place being 

 taken by two oblong membranous sacs, which act as 

 respiratory organs. .Mso placed here, in the females 

 are the ovisacs, which are said to contain numerous 

 good-sized eggs. This statement appears in all 

 works on Natural History to which I have .access. 

 I had always received it without question, until some 

 lime since, whilst preparing sundry objects for the 

 microscope, when upon jiressing a specimen between 

 two gla-ss slips, to express the contents of the 

 attenuated body and ovisac, I was greatly surprised al 

 the extrusion, not of a mass of eggs, as I expected but 

 of a veritable host of tiny Caprellae all perfectly 

 formed, and ex.actly resembling the parent in every 

 respect, except that the heads were larger th.an in the 

 adult. The number of young was great, and how 

 they, with their long legs, and two pairs of antennae, 

 could have been all packed in the ovisac continues to 

 be a marvel tome. From this .single specimen, which 

 improbably difiers from other members of the family 

 Caprellidae, it would seem that instead of being 

 oviparous, as represented, it is really ovoviviparous, 

 and the lar\al existence is pas-sed in ovisac of parent. 



This creature is by no means uncommon on the 

 I'.nglish coast, and w'here\er I'ycnogons are to be 

 found, there, almost certainly, will CVr/zv/Zd lie associ- 

 ated with them. The best way to find them is to 

 turn over flat stones and pieces of rock, al alxiut low 

 water mark, at spring tides, when amongst the 

 miniature forests of zoophytes and immature seaweeds, 

 particularly when dirty in appearance, the.se skeleton 

 shrimps will soon be detected. They have a remark- 

 able habit of clinging with two hind claws to the 

 rock, and then incessantly swaying to anil fro, as if 

 .agitated by some current in the water, but when kept 

 in an a<|uarium, where the water is perfectly still, the 

 movement hardly ever ceases. This action so closely 

 resembles that of colonies of young zoophytes, when 

 laved by marine currents, that I lake it to be a 

 protective movement, more particularly as in colour, 

 and in their jointed body they so closely resemble the 

 zoophytes. Combining the likeness with the move- 

 ment, we have, probably, here an instance of 

 protective mimicry highly conducive to the preserva- 



tion of the creature. 



EllWARll IL ROBERT.SON. 



