438 



Mr. A. E. Hilton : Tracheae of Silkworm, showing foldings or 

 thickenings of membrane rather than a definite continuous fibre. 

 (See p. 405.) 



Mr. H. Morland : Abnormal forms of Melosira Dichiei^ 

 Thwaites, showing the valves fitting into one another somewhat 

 after the style of flower-pots. The slide is from a set of the 

 Norfolk Diatoms mounted by the late F. ELitton. 



April 20th, 1900. 



Mr. R T. Lewis: The male of the Great Cattle Tick — the 

 " Bont Tick " of the Dutch colonists of the Cape and Natal — 

 Amhlyomma hehrcEum Koch, This Tick is one of the commonest 

 Cattle Ticks in Cape Colony and Natal. The word " bont " is 

 Cape Dutch for " variegated," and the animal well deserves the 

 appellation, for the male is beautifully coloured, green, gold and 

 purple, while the female, although in the main of a dark 

 chocolate colour, has a purple and yellow pattern on the shield 

 with yellow joints to the legs, 



Mr. A. E. Hilton : Portion of skin of Silkworm, Boinbyx mori, 

 showing two spii^acles, the main tube connecting the same, and 

 the branching trachese. 



Mr. A. Earland : Specimens of Orhulina univey^sa (d'Orbigny) 

 laid open to show the internal Globigerine shell. 



The genus Orbulina is typically a hollow sphere, but if a 

 number of specimens are laid open a few will be found to contain 

 a more or less perfect " Globigerina " attached to the interior of 

 the sphere by numerous very delicate spines. Hence the theory 

 that Orbulina is only a life stage of Globigerina. It is supposed 

 that the Globigerina for protective purposes or some unknown 

 reason surrounds itself with a spherical shell ; the early Globigerine 

 chambers being then of no further use are gradually dissolved and 

 absorbed, until at last the sphere becomes quite hollow (Orbulina 

 in its typical form). 



Note (1) The spines attaching the chambers to sphere. 

 (2) The more or less eroded nature of the final chambers of the 

 Globigerine shell. (3) The Globigerine shell visible through the 

 external shell of the sphere in one or two of the smaller specimens. 



May 4th, 1900. 

 Mr. W. E. Traviss : Decrepitating Quartz, from Branchville, 



I 



