ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 615 



is seen in the dorsal view, while the other half is seen in the 

 ventral. 



On the thorax there is a distinct pair of eyes, furnished with 

 very convex lenses, just as in Rhyncholophus. It further bears 

 several long setae, of which the pair situated between the eyes is 

 distinctly fringed. This special pair of setae on the thorax when 

 seen under a low power, especially as it is placed near the black eye- 

 spots, leads one to suppose that we have here a respiratory organ, 

 similar to the stigma of the Oribatidae ; but a higher power shows 

 distinctly that they are nothing but an ordinary capillary structure. 

 On the thorax there are also three longitudinal lines, branched in a 

 tree-like fashion behind, and two transverse lines ; and these divide 

 its whole dorsal surface into several areas, three of which occupy the 

 entire central space. 



On the lower surface the thoracic segmental lines are seen dis- 

 tinctly running between the coxal plates of the second and third 

 pairs of legs. The segmental lines of the back also pass on to the 

 lower surface bending forward in the middle of the abdomen. The 

 segmental lines of the more anteriorly situated abdominal segments 

 could not be distinctly traced on the lower surface. 



5. Crustacea. 



Perception of Colour by Crustacea.* — C. De Merejkowsky fol- 

 lowing Sir John Lubbock's investigations into the perception of 

 colour by the lower animals, has experimented on Crustacea, especially 

 larvae of Cirripedes and a Copepod. In darkness, the animals 

 disperse to all sides of the vessel in which they are kept ; if day- 

 light is admitted through a slit, they congregate near the slit, and 

 behave similarly towards monochromatic light, of whatever colour. 

 Using two slits at an angle of 40° with each other and admitting 

 white light by one and a monochromatic light by another, he 

 finds that most, if not all, prefer the white light, but pale colours 

 (yellow, green, pale red) also attract a few individuals. When two 

 monochromatic lights are used, the brighter is preferred; with two 

 rays of equal brightness the animals are equally divided between 

 the two. Any superiority in the amount of light admitted attracts 

 the bulk of the colony, whether the light is monochromatic or not. 

 Thus it is seen that these animals appreciate only the quantity of 

 the light, or the intensity of the vibrations which produce it, and are 

 only sensitive to colour as implying a certain amount of light. 



Mediterranean Crustacea, j — L. Joliet describes a parasitic Crus- 

 tacean which he found under the form of small, ovoid, reddish bodies 

 in the general cavity of the Alcyonarian Paralcyonium elegans. Not 

 at all unlike a tardigrade at first sight, their two pairs of antennae and 

 the form of the hinder end of their bodies showed that they could 

 be nothing else than crustaceans. The author soon found that the 

 creature under examination belonged to the genus Lamippe, of which 



* Comptes Eendus, xciii. (1881) pp. 160-1. 



t Arch. Zool. Expe'r. et Gen., x. (1882) pp. 101-20 (1 pi.). 



