598 SUMMARY OF CTJKRENT RESEARCHES RELATING TO 



eyes are quite invisible. Now, as every ray of homogeneous light 

 which we can perceive at all ajjpears to us as a distinct colour, it 

 seems probable that these ultra-violet rays must make themselves 

 apparent to the ants as a distinct and separate colour (of which we can 

 form no idea), but as unlike the rest as red is from yellow, or green 

 from violet. The question also arises whether white light to these 

 insects would differ from our white light in containing this additional 

 colour. At any rate, as few of the colours in nature are pure colours, 

 but almost all arise from the combination of rays of different wave- 

 lengths, and as in such cases the visible resultant would be composed 

 not only of the rays which we see, but of these and the ultra-violet, it 

 would appear that the colours of objects and the general aspect of 

 nature must present to them a very different appearance from what it 

 does to us. Similar experiments which Sir John also made with 

 some of the lower Crustacea point to the same conclusion ; but the 

 account of these he reserves to a future occasion. 



Some experiments made on the sense of direction possessed by 

 ants are also described, and on their power of recognizing friends, 

 with some facts which appear to show that ants, by selection of food, 

 can produce either a queen or a worker at will from a given egg. 

 Some ants observed in 1874, are still living and in perfect health — 

 more than seven years old — by far the oldest insects on record. 



13. Myriapoda. 



Structure and Affinities of Carboniferous Myriapoda.* — Mr. S. 

 H. Scudder, as the result of an examination of Ewphoberia major M. 

 and W., finds that the structure of the Carboniferous EuphoberidsB 

 differs so much from that of the modern forms, that they cannot be 

 referred to the Diplopoda or Chilopoda, but should be placed in a new 

 sub-order, for which the name of Archipolypoda is proposed. 



y. Araclmida. 



Anatomy of Epeira.j — W. Schimkevitsch describes the chitinous 

 layer of Epeira as being composed of three layers ; the thickenings 

 below the " lungs," which Bertkau regards as due to the coalescence of 

 setae, are said to be due to folds of these three layers. The structure 

 of the sheath of the setae is more complicated than is ordinarily sup- 

 posed ; it is composed of two funnels, one within the other, and having 

 near the chitiuogenous layers a common enlargement which opens 

 by a wide pore. A general sarcolemma, enveloping the whole of a 

 muscular fibre, is only to be observed on the spiral muscle of the 

 poison-glands. The adipose cells of the cephalothorax are not, as 

 Plateau thought, confined to the stomach, but are to be found in all the 

 intra-organic spaces. The ganglia of the appendages give off, on 

 each side, two nerves ; the maxillary ganglion gives off three pairs. 



After a discussion of various nervous and sensory parts, the author 

 states that the sucking organ is provided with a veritable sphincter- 

 muscle ; the cells of the posterior stomach are altogether comparable 



* Amer. Jouni. Sci., xxi. (1881) pp. 182-6. 

 t Zool. Aiizeig., iv. (1881) pp. 231-8. 



