130 Chronicles of Science. [Jan., 
perfectly constant colorational difference, and others which are not 
perfectly constant in the larva, but none whatever in the imago ; or by 
several slight, but constant structural differences in the male imago, 
but none whatever in the female; or by a slight but constant struc- 
tural difference in both male and female imago ; or by very strong 
structural and colorational differences in the larva, and in all pro- 
bability by a constant structural difference of generic value in the 
female imago, the males being to all external appearance identical, 
and the two insects belonging to different genera; or lastly, by 
marked and constant differences, either colorational or structural, or 
both, in the larva, pupa, or imago states. Of each of these he 
gives examples; and remarks that for his own part, as on the most 
careful consideration he is unable to draw any definite line in the 
above series, and to say with certainty that here end the varieties, 
and here begin the species, he is therefore irresistibly led to believe 
that the varieties gradually strengthen and become developed into 
species, and that the difference between them is merely one of mode 
and degree. 
Professor Claus finds that in the Ostracode division of Crus- 
tacea, the heart is sometimes present and sometimes absent. ‘This 
remarkable fact was demonstrated by the discovery of a heart 
beating with regular pulsations in Cypridine, while it is known 
that in the other two families, Cypride and Cytheride, the heart is 
absent. ‘The same curious circumstances obtain in the Copepoda, of 
which the families Cyclopidee, Harpactidee, and Coryceeida possess 
no heart, while in the other two families, Pontellide and Calanide, 
it is always present. M. Claus has also detected in the Cypri- 
dinze, in addition to the large, paired, compound eye, an accessory 
single eye, simple and median, perfectly similar to that which exists 
in addition to the compound eye, in the Daphnie. The Cypri- 
dine thus appear to differ widely from the other two Ostracode 
families, not only in these respects, but also as regards their appen- 
dages, the three anterior pairs of which are employed by them as 
locomotive organs, as is the case with all Entomostraca during their 
Nauplius phase. 
It is very unfortunate that disputes should arise upon scientific 
questions to such a degree as that either disputant should indulge 
in personalities, but the scientific world has been of late anything 
but edified by the discussions between Dr. Carpenter and Professor 
William King of Belfast. ‘The foraminiferous character of the 
fossil Eozéon canadense, distinctly asserted and minutely described 
by Dr. Carpenter, has been attacked by Dr. King, and much heat 
is introduced imto the discussion. Another subject sets them also 
at variance, a matter of fact depending upon experience and acute- 
ness of observation, viz. the microscopic structure of the shell of 
