554 General Notes. | May, | 
least of the chromatophores is to diminish the transparency of the 
skin and thus to lower the action of even moderate light when it 
begins to affect injuriously the organism. 
Tae METAMORPHOSIS OF PENEUS.—Dr. W. K. Brooks, in his 
account of the metamorphosis of Peneus (Johns Hopkins Univer- 
sity Circulars, Nov., 1882), noticed in the January number 
the NATURALIST (p. 90), says :` 
“Those familiar with the literature of the subject will recollect 
that Fritz Müller kept under observation until it changed into a 
protozoéa, a nauplius which he captured at the surface of the 
ocean. He also secured, in the ocean, a very complete series of 
larvæ, through which he identified his protozoëa with a young 
Macrouran with the characteristics of the genus Peneus. He did 
not rear the nauplius from the Peneus egg, nor did he actually ob- 
serve the transformation into the young Peneus. Certain over- 
cautious naturalists have therefore refused to accept his conclu- 
sions until more conclusive proof should be furnished.” 
Dr. Brooks then proceeds to state that he has captured the pro- 
tozoëa of Peneus and reared it in confinement, witnessing every 
one of the five molts between the youngest protozoéa and the 
oung Peneus. “The whole metamorphosis of Peneus has 
therefore been actually witnessed and there is no longer anyroom 
for criticism.” : 
If Dr. Brooks will read Fritz Miller’s two papers on the subject 
(Arch, Naturgesch., Bd. xx1x., Zeitschr. wissensch. Zool., Bd. xxx), 
he will learn that Müller did zoż keep the nauplius under A 
sumed relation between the protozoéa and the n 
over-cautious naturalists” wished to see proved eit 
the nauplius from the egg of Peneus, witnessing thetra 
of the nauplius into the protozoëa, or discovering intermeti 
stages between the nauplius and the protozoëa. Brooks observa 
tions have no bearing on the question whatever. 
the connection between the stages older tha hows 
That the nauplius belongs to the same series, he has not $ 
In fact, his youngest protozoéa is an older stage than the Yali a 
protozoéa secured by Müller. He has riveted the links in pe 
chain that were closely joined before, but has not tou ) 
weak spot! he 
From the complete disappearance of the exopodites from a 
five pairs of legs and the simplicity of the abdominal APRo Jara - 
in the oldest stage observed, it would appear that Broom se 
belongs to the genus Sycionia rather than to Peneus. uncom- 
The larval stages of the Peneidz seem to my. Miller 
mon in the warmer seas. Besides the published figures ee 
