ZOOLOGY AND BOTANY^ MICROSCOPY, ETC. 49 



cells may be seen frequently to end below in long colourless tails or 

 threads which are in connection with a mass of tissue lying below them, 

 and on the outside of the epithelial tissue. This mass consists of stellate 

 cells, the points of the stars being produced into long colourless threads, 

 which are in some cases connected with the threads from the outer 

 columnar cells. Owing to the greater size of Lingula the modified 

 epithelium is there larger and easier of detection ; there are three regions 

 of especially modified tissue on the arms. All these tracts probably 

 correspond to the tracts of specialized tissue described as occurring in 

 some articulate Brachiopods, and regarded as sense-organs. Their 

 intimate connection with nerve-fibres and cells supports this view of 

 their sensory nature. 



Arthropoda. 

 o, Insecta, 



Observations on Ants, Bees, and Wasps.* — Sir John Lubbock has 

 published the eleventh part of his observations. He is of opinion that, 

 though there may be nests of Formica sanguinea without slaves, an 

 experiment which he has made seems to indicate that the slaves perform 

 some important functions in the economy of the nest, though it is not 

 yet determined what that function exactly is. 



With regard to Ant-guests, he points out that Dr. Wasman has 

 confirmed his observations, in opposition to Lespes, that, while ants are 

 deadly enemies to those of other nests, even of the same species, the 

 domestic animals may be transferred from one nest to another, and are 

 not attacked. Attention is next drawn to Prof. Emery's observations on 

 mimicry among ants. 



With regard to the colour- sense, Prof. Graber has confirmed Sir 

 John's observations on Ants and Daphnias, by which he showed that they 

 are sensitive to the ultra-violet rays, by similar observations on earth- 

 worms, newts, &c. Light was found to act on decapitated earthworms, 

 though the diiferences were not so marked ; the same held good for newts, 

 when their eyes were covered over, and Graber hence concludes that the 

 general surface of the skin is sensitive to light. Forel has made some 

 observations on ants, the eyes of which were carefully covered by 

 opaque varnish, so that they were rendered temporarily blind. 



From experiments made with Platyartlirus, which have no eyes, the 

 author found that they made their way into the shaded portion of a 

 partly covered nest, and he remarks that it is " easy to imagine that in 

 unpigmented animals, whose skins are more or less semitransparent, 

 the light might act directly on the nervous system, even though it 

 could not produce anything which could be called vision." 



Sir John's experiments lead him to differ from M. Forel, who believes 

 that bees have a certain sense of direction. The power of recognizing 

 friends is discussed at some length, but the explanation of the fact still 

 remains obscure. The most aged insect on record is a queen of Formica 

 fusca which lived for fifteen years ; what is much more extraordinary is 

 that she continued to lay fertile eggs ; fertilization took place in 1874 at 

 the latest, and there has been no male in the nest since then, so that the 

 spermatozoa of 1874 must have retained their life and energy for thirteen 

 years. 



=f Journ. Linn. Soc. Lond., xx. (1888) pp. 118-36. 

 1889. E 



