172 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and salts of lime with an undetermined base (in Phasmids). There is 

 sometimes distinct polymorphism. The intra-cellular mechanism of 

 excretion is complex ; the transport of excreted substances into the gut 

 is partly due to a pressure from newly-formed material and partly to 

 muscular action. There are accessory functions of eliminating colouring 

 matter, and sometimes of forming calcareous materials. The gut, the 

 integument, and the adipose tissue may also aid in excretion. 



Behaviour of Nucleolus in Spermatogenesis of Cockroach.* — 

 J. E. S. Moore and L. E. Robinson find in the nucleus of the 

 spermatogonia of Periplaneta americana, a chromatin-nucleolus, which 

 is expelled in the formation of the spindle, and degenerates in the 

 plasma. Another nucleolus arises de novo in the daughter-cell. 



Before the maturation divisions there is a longitudinally split 

 chromosome -like body present, comparable to the accessory chromosome. 

 It also degenerates in the plasma. 



In the spermatid, finally, there is again a nucleolus, differentiated 

 from the chromatin of the nuclear framework. It divides, and one 

 half is extruded into the plasma, while the other disappears in the 

 nucleus. 



Ovaries of Mallophaga and Pediculidse.f — J. Gross has examined 

 these and finds a quite striking agreement in the structure of the egg- 

 tubes and eggs of the two groups. This extends to details. In both 

 groups the ovaries are fascicular, with at most five egg-tubes. They 

 are always poly trophic, without nutritive chambers. There is in both a 

 small number of nutritive cells — five appears to be the ruling number ; 

 and, further, the egg formation appears to go on in the same way. 

 There is, in fact, a whole series of striking resemblances, such that, as 

 far as the female sex-organs go, the two groups might be united in one 

 order. The Pediculidse do not show such agreements with the 

 Hemiptera. 



Sense Organs of Insects.:}: — E. Rohler reviews the known facts 

 regarding these in insects generally, and gives a detailed account of 

 them in Tryxalis nasuta, and of the antennary organs in Musca 

 vomitoria. In the former there are three types upon the antennae. 

 There are sensory cones in pits (sensilla cceloconica of Schenk), which 

 are markedly different as regards numbers in the two sexes, and which 

 probably have a smelling function. The second type consists of surface 

 cones (sensilla basiconica of Schenk), which are organs of touch ; and, 

 lastly, there are bristles which, if sensory, are but relatively coarse touch 

 organs, and which do not regulate the movements of the antennas. 

 Of the groups of hair around the mouth some serve for the mechanical 

 examination of the food, while others subserve the function of taste. 



The Oil of Indian Mites.§ — E. G. Hill makes a note on the chemical 

 composition of the oil which is extracted from a red mite, Bucella 

 carniola (Trombidium grandissimum), a creature about half-an-inch 



* Quart. Journ. Micr. Sci., xlviii. (1905) pp. 571-83 (2 pis.). 



t Zool. Jahrb. Abt. Anat., xxii. (1905) pp. 347-86 (2 pis. and 2 figs.). 



t Tom. cit., pp. 225-88 (2 pis. and 1 fig.). 



§ Journ. and Proc. Asiatic Soc. Bengal (1904) i., pp. 74-80. 



