Miscellaneous. 481 



Allied to Typhis Sowerbii, but distinguished from it by its squarish 

 shape, thick and nodulous varices, closely appressed spines, and the 

 decided lateral direction of the canal. 



Typhis arcuatus. Typ. testd corned, fusiformi ; quudrifariam va- 



ricosd ; varicibus arcuatis, inermibus, ad spiram bene distinctis, 



superne in tubulis desineuiibvs ; tubitlis complanatis, ascendentibus; 



canali mediocri recurvo. Axis o\ lin. 



Hab. Cape of Good Hope. Dredged on the L'Agulhas Bank in 



from forty to fifty-four fathoms. 



Shell fusiform, of a horn-colour ; the varices arcuate, terminating 

 in the tube, and ascending the spire even to the apex, giving it a 

 pyramidal shape. The character of the bowed spineless varices is 

 peculiar, and altogether it is a very distinct species. 



Typhis nitexs. Typ. testd ovali, albidd, Icevigatd, nitidd ; quadri- 

 fariam varicosd ; varicibus actttis in spinis excentricis desinentibus ; 

 tubulis rectis ; canali brevi recurvo. Axis 4 lin. 

 Hab. Straits of Macassar, Indian Archipelago. Dredged from 

 among gravel and coral in eighteen fathoms. 



Looking from the apex, the spines and tubes will be seen to be 

 disposed in an elegant spiral manner about the spire. It is the first 

 species, as far as 1 am acquainted, that has hitherto been found in 

 the Indian seas, and is at the same time the smallest yet recorded. 



MISCELLANEOUS. 



ON THE MICROSCOPE. MEANS OF REMEDYING THE DEFECT OF 

 artificial LIGHT. BY J. W. GRIFFITH, MD., F.L.S. * 



It must have been repeatedly noticed by microscopic observers of 

 any experience, that the only agreeable time for making minute ob- 

 servations is during daylight, and that examinations made at this 

 time only can be relied on. The pure white daylight, furnished by 

 reflection of the sun's rays from large floating cumuli, is that which 

 best illuminates microscopic objects ; whilst the orange or reddish- 

 yellow light of a lamp or candle wearies the eye incomparably 

 more than the softness of daylight. There is also a marked glare 

 with candle or lamplight : this is very annoying to most observers ; 

 so much so as to compel many to use the microscope by daylight 

 alone, which few can have the opportunity of doing. To remedy 

 this defect of artificial light, by showing the method of rendering it 

 as white as daylight, is the object of the present communication. 



The imperfections of lamp or candlelight appear to me to arise 

 mainly from two causes : 1st, its being monochromatic; 2ndly, the 

 colour in excess being that which is most intensely luminous, viz. 

 yellow. The first renders us totally unable to appreciate colour ; 

 the second causes a very unpleasant and injurious glare. It oc- 

 curred to me that these might be overcome from the following con- 

 siderations. 



It is weU known, that by the combination of a certain colour form- 



* From the Medical Gazette, for Nov. 25, 1843. 



