PBOGRBSS OF MICROSCOPICAL SCIENCE. 
93 
hands to represent the best work of the microscope. The transverse 
lines, about 89,000 to the inch, are shown indifferently well, and the 
finer longitudinal ones are so drowned and obscured as to lead Dr. 
Woodward to doubt their existence. More careful adjustment and 
painstaking manipulation, or a better glass,* would have dispelled 
most of the diffraction lines, lifted the hazy veil, and enabled the 
observer to see this beautiful shell as others have seen it. It would 
also have saved him from taking the position of doubting the positive 
testimony of others when he has nothing but negative testimony 
himself to offer. The present writer had seen the fine longitudinal 
lines in question, 95,000 to the inch, counted them, and given the 
results to the public through the columns of the ' American Naturalist ' 
nearly three years ago, and has seen them many times since. Less 
than a month ago, as had been the case before, both sets of lines were 
seen at once, and the face of the shell appeared covered with distinct 
and regular checker work ; an appearance not presented or approached 
by any of Dr. Woodward's photographs. Both Dr. Woodward and 
myself were fortunate, or perhaps unfortunate, in having to work on 
Moller's finest and most difficult specimens. Perhaps Dr. Woodward 
might have got both sets of markings if he had been as fortunate 
as was Mr. Hickie f in having coarser specimens to study." 
The Structure of a Larval Cirripede. — Mr. Henry Davis, an accu- 
rate and careful observer, has noticed some poicts in the structure of 
the cirripede, additional to those described by Mr. Darwin in his 
celebrated work. The original points of his paper J refer to the 
carapace of this animal. He says : — Darwin speaks of it as being 
provided with two points at the posterior end, and with a pair of pro- 
jections, like short horns, in front (which he thinks may be called the 
ears), but he says nothing of the very noticeable corrugated crest 
running over the back at the junction of the valves : and, failing any 
published figures of this larva, some doubt may be attached to the 
specific name I have appended. The external microscopic structure 
is very interesting, and has been strangely neglected — only " marks 
and lines " are recorded ; but under a binocular microscope, with a 
quarter-inch objective and reflected light, we can see the surface 
covered with deep thin walls or ridges, generally parallel, but in parts 
tending to confluence ; their outer edges are serrated, and the thin 
walls are strengthened by a sort of buttresses, only seen in certain 
lights. Towards and over the " ears " the ridges are so modified as 
to leave hexagonal depressed spaces ; while in one spot, beneath which 
the enclosed larva bears its eyes, the shell is left beautifully smooth 
and transparent. This creature, then, with its " toughened glass " 
window, is remarkably well protected ; in storms or any danger he has 
only to shut up his shells, hold on by his antennae, and keep a good 
look-out. 
* [It is perfectly absurd to suppose tliat Dr. Woodward was not furnished 
with the very best glass, and as to careful adjustment that is an equally un- 
necessary remark. — Ed. ' M. M. J.'] 
t ' M. M. J.,' March 1, 1876, p. 123. 
X • Journal of the Quekett Club,' May. 
H 2 
