QUARTERLY CHRONICLE. 219 
body goes on, whilst the posterior part remains comparatively 
quiescent. 
Polydora spirillum is he remarks very easy to obtain for 
examination and to trace. His observations on this worm 
are of importance, as clearing up a confusion existing as to 
its relation to Leucodore of Johnston, which M. de Quatre- 
fages has done much to increase. The Leucodore of Johnston 
is the Polydora of Bosc; whilst what Claparéde mistook for 
Leucodore of Johnston, as also has De Quatrefages, is really 
a species of Nerine of Johnston, not having the characteristic 
bristles of the fifth segment seen in both Polydora of Bosc 
and Leucodore of Johnston. It further is evident from these 
researches that Nerine, Spio, and Polydore are most closely 
allied, and ought not to be widely separated from each other 
in different families, as is done by M. de Quatrefages. 
The young stages of Phyllodoce maculata, Cirsted, are the 
last described in this paper. ‘They thrived very readily in 
confinement, and enabled Mr. Agassiz to confirm and supple- 
ment to some extent Max Miiller’s observations on the same 
genus. 
The paper concludes with some observations on the types 
of development in annelids. While considering Claparéde’s 
division the best that has been yet proposed, Mr. Agassiz 
considers that it must share the fate of Busch’s, Miiller’s, and 
Schultze’s classifications, since our knowledge of the young 
forms of annelids is at present so very limited. ‘The presence 
of temporary bristles is a good criterion for one division, but 
the negative character of their absence alone is objectionable. 
Two larve are figured which the author cannot refer to 
their adult forms, and which belong to the group Metachete 
of Claparéde. One is remarkable as being very possibly the 
young form of a Turbellarian worm, though itself provided 
with bristles and having a segmented character. The other 
is remarkable as being parasitic on the interior of the cara- 
pace of lobsters, and possessing most characteristic serrulate 
bristles. Myr. O. C. Marsh showed Mr. Agassiz a series of 
fossil annelids, which, it is of great interest to note, were all 
provided with bundles of the large, rough sete found as 
temporary characters in living embryonic annelids. 
MISCELLAN EOUS.—Reagents—Cohnheim and Kolli- 
ker strongly recommend the use of chloride of gold for demon- 
strating various points in histology. ‘Tissues which have been 
soaked for some time in a weak solution of it, and afterwards 
exposed to light, are found to exhibit certain parts, e. g., nerve- 
fibres, connective tissue, corpuscles, and cells in general, 
stained of a bluish, violet, or reddish colour, while other 
