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PROGRESS OF MICROSCOPICAL SCIENCE. 
The Metamorphoses of the Crane-fly and Blow-fly. — A capital paper 
on this subject is reported in the ' Journal of the Quekett Club ' 
(May). It is by Mr. A. Hammond. The paper is much too long for 
abstract, but we may state that it deals very fully with the development 
of the two insects, and that it calls in question some of the views 
promulgated by Mr. Lowne. The author states that the tendency of 
his observation is to disprove the distinctive character of the develop- 
ment of the cephalic and thoracic segments in the crane-fly, but to 
retain it in the blow-fly ; and if this be true, seeing that in either 
case the development originates in structures which are distinctly 
homologous, the question arises whether the two methods are separated 
by an impassable gulf, or whether the study of other insects, by re- 
vealing the existence of intermediate links between the form, disposi- 
tion, and connections of these structures in the one case and the other, 
may bridge over the chasm which at present seems to separate the 
two methods, and indicate a gradation of modes of development, as 
well as of external form and internal structure. 
A New Diatom. — Mr. A. Cottam thinks that a new species of diatom 
has been found by Mr. Martin, at Banana Creek, in the Congo Eiver, 
west coast of Africa. Differences of opinion on this point existed 
between Mr. Cottam and Mr. Kitton ; but, from an examination of 
Dr. Greville's specimens in the British Museum, Mr. Cottam arrives at 
the conclusion that the present form is a new species. He says that 
** the new African diatom appears to agree with A. Kittoni in the 
arrangement of its granulation, although the granules are smaller. 
It differs from it in generally having a small umbilicus, and in its 
processes, which, instead of being mammiform, have distinct circular 
hoods. It appears to him to differ from A. Johnsonii in the arrange- 
ment and size of its granules (although size is not of much value as a 
specific distinction), but especially in the fact that A. Johnsonii has 
no raised portions under the processes, and has granules of very 
different sizes on the same valve. They agree in having an umbilicus, 
although its presence in the new form is not invariable ; and in these 
too the form of the processes is more alike, although more highly 
developed in the West African form." He goes at considerable 
length into the subject in his paper, which must be read for further 
information.* 
The Structure of Connective-tissue Corpuscles is still the subject of 
debate among the German histologists. In Max Schultze's ' Archiv,' 
or rather what used to be Max Schultze's, and is now the ' Archiv 
fiir mikroscopikische Anatomic,' f is a paper on the above sub- 
ject by W. Waldeyer. An abstract of his communication is given 
by the ' Medical Eecord ' (June 15). It is divided under the fol- 
lowing heads: — 1. The so-called Flat-cells ("Flatten Zellen") of the 
Fibrillar Connective Tissue. — Under this title the author groups the 
cells of the loose fibrillar connective tissue and of the formed fibrillar 
connective tissue of tendons and fibrous membranes. The tendon- 
cells do not represent simple rectangular plates, but are complicated 
♦ • Journal of the Quekett Club,' May. f Band ii. p. 176. 
