NOTES AND MEMORANDA. 263 
makes on Mr. Erasmus Wilson, who wrote a paper on the subject of 
this arachnid, which is published in the ‘ Philosophical Transactions of 
the Royal Society ’ for 1842. It is pointed out that Mr. Wilson has 
fallen into the most terrible errors in his description of the animal. 
—A paper by M. Poincarré is also of interest to the histologist. 
It is upon the “ History of the Thyroid Body.” The author states 
that he has examined more than seventy glands, and these have been 
in all vertebrate animals, and he states that there is a general resem- 
blance of all to each other. But he remarks that while the presence 
of closed vesicular spaces is undoubtedly a characteristic feature in 
most thyroids, yet that man’s thyroid body is to some extent an excep- 
tion. He found that in human glands cysts were extremely common. 
Out of 106 specimens examined, no less than forty-three bore cysts 
within them.—Another paper, which is of some interest to the micro- 
scopic anatomist, is that upon “ The Origin of the Cranial Nerves,” 
by M. Duval. This is the conclusion of a series. The magnifying 
power employed is, of course, extremely low. 
Archiv fiir Mikroskopische Anatomie, herausgegeben von La Valette 
St. George und W. Waldeyer. 13 Band, 4 Heft. Bonn, 1877.— 
This number contains some very valuable and exquisitely illustrated 
papers. First in order is a long disquisition on the general structure 
of glands, by Dr. M. Nussbaum. This paper is illustrated by a plate 
containing many magnified representations of sub-maxillary and other 
salivary glands, of the glands of the pyloric end of the stomach, of 
the cesophageal glands, &c., &e. The most interesting paper in the 
entire number is that of Herr F. E. Schultze, on Spongicola fistularis. 
This is illustrated by three plates, in which we see the difficulty 
that the author must have had in referring the animal either to the 
Spongiade or to the Hydrozoa. It is exceedingly like the animals of 
both classes, and is really a connecting link of an extraordinary kind. 
We shall notice the rest of the contents in our next number. 
NOTES AND MEMORANDA. 
Angle of Aperture, Increase or Diminution of.—On this point 
there appears to be a considerable divergence of opinion at the present 
moment. We therefore publish a portion of a letter which has been 
addressed by Mr. Carl Reddots to the editor of the ‘ American 
_ Journal of Microscopy.’ He says :—* I find the following in the report 
of proceedings of the Dunkirk Microscopical Society, in this Journal 
for January 1877: 
«“¢ Professor Smith took a position radically opposed to many 
of the received ideas, and in favour of lenses of the widest angle of 
aperture for all kinds of work, even going so far as to express his 
* opinion that most of the work in histology and pathology done with 
the so-called ‘ working lenses’ of narrow angle, would require further 
