ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
443 
and Insects are less closely related to one another than Annelids and 
Insects. He thinks there is reason for believing that Annelids, Crus- 
taceans, and probably Limuloids, were derived independently from the 
Eotifera. The Nauplius-larva shows that the Crustacean type is not 
successional to a many-jointed Annelid, but rather to some Pedalion-like 
Rotifer. 
The diversities and agreements of Limuloids from and with Crus- 
taceans suggest a derivation nearly like that of the Crustacean type, but 
probably not from Crustaceans. 
A line of succession from Worms to Myriopods and from Myriopods 
to Insects has not been proved by geological discovery, but is suggested 
by Peripatus and by certain resemblances between Annelids and Myrio- 
pods; Scudder has pointed out the resemblance of the Carboniferous 
Palseocampa to the caterpillar of Arctia. 
In both Insects and Spiders the rise of grade involved a general 
concentration of the structure towards the cephalic nervous centre. The 
fact that as higher Insects rise in grade the larval stage becomes lower 
and lower in embryonic level suggests that the larval stage results from 
an attendant retrograde embryonic change to a line parallel with the 
Myriopod, and beyond to the memberless condition of a worm. If we 
accept the view that, as many zoologists hold, the two pairs of maxillae 
of Insects belong to a single body-segment, we find that the thorax and 
head of an Insect are essentially homologous with the head of a tetra- 
decapodous Crustacean. 
a. Insecta. 
Insect Sight and the Defining Power of Composite Eyes.* — Mr. A. 
Mallock is led by his observations and calculations to conclude that 
Insects do not see well, at any rate as regards their power of defining 
distant objects, and their behaviour favours this view. They have, how- 
ever, an advantage over simple-eyed animals in the fact that there is 
hardly any practical limit to the nearness of the objects they can examine. 
With the composite eye the closer the object the better the sight, for 
the greater will be the number of lenses employed to produce the 
impression ; in the simple eye, on the other other hand, the focal length 
of the lens limits the distance at which a distinct view can be obtained. 
Of the various forms of Insects examined, the best eye would give a 
picture about as good as if executed in rather coarse wool-work, and 
viewed at a distance of a foot. 
Phylogeny of the Pieringe.l — We must be content with calling 
attention to Dr. F. A. Dixey’s paper on this subject ; he confines himself 
to the evidence afforded by wing-markings and by geographical distri- 
bution. The subject is treated with great detail, but is intelligible 
only to the professed student of the group in the present state of the 
investigation. 
Notes on Micro-Lepidoptera.j — Dr. T. A. Chapman deals with such 
forms as have larvae that are external feeders, and expresses his belief 
that the Zygaenidae, Limacodidae and Eriocephalidae form a group which 
* Proc. Roy. Soc. Lond., lv. (1894) pp. 85-90 (3 figs.), 
f Trans. Entomol. Soc. Lond., 1894, pp. 249-334 (3 pis.), 
t Tom. cit., pp. 335-50 (2 pis.). 
