ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
27 
INVERT EBR AT A. 
Chlorophylloid Pigments.* — Miss M. I. Newbigin gives an account 
of her observations on chaetopterin, “ enterochlorophyll,” bonellin, and 
other green pigments in Invertebrates. She describes the various re- 
actions of chaetopterin, and notes as points of special importance that 
while chaetopterin itself is indefinite in colour and strongly fluorescent, 
and exhibits a complex spectrum, the action of reagents tends to produce 
pigments of bright definite tint and simple spectrum, which may be 
soluble in water and are without fluorescence. Certain points of re- 
semblance to bonellin are also of much interest. 
Enterochlorophyll from Molluscs and Echinoderms is closely related 
to chaetopterin, but differs a little in spectrum, colour, and solubility. 
It has an apparent resemblance to plant chlorophyll in fluorescence, in 
its association with a yellow lipochrome, and in its spectrum ; but its 
resemblance to chaetopterin tends to disprove its identity with the plant 
pigment. The balance of evidence is in favour of an affinity between 
bonellin, chaetopterin, and enterochlorophyll. “It is interesting to note 
that in many groups of Invertebrates, either in the same animal or in 
related forms, there may occur two different sets of green pigments, 
distinctly marked off from one another, but connected by the derivatives 
of the more complex series. Such are bonellin and thalassemin in the 
Ecliiuridae, chaetopterin and the pigment of Eulalia in the Chaetopoda, 
enterochlorophyll and the pigment of Acmsea in the Mollusca ; it is 
probable that there are many other cases.” 
It seems then that there exists in Invertebrates a widely spread 
group of pigments occurring primarily in connection with the alimentary 
tract or its outgrowths, and characterised by forming in alcohol fluores- 
cent solutions of indefinite colour which exhibit a complex spectrum, 
consisting when fully developed of five bands. They have only a 
superficial resemblance to chlorophyll, and they so far resemble the 
bile pigments of Vertebrates that they occur mingled with the contents 
of the gut, and at least in some cases are eliminated with the faeces. Of 
their primary function nothing is really known. As a general designa- 
tion the term “ enterochrome ” or “ jDolychrome ” is suggested. 
Nervous System of Invertebrates.! — Herr J. Steiner has extended 
his study of the central nervous system to Invertebrates. He has defined 
the brain as the general motor centre in connection with at least one of 
the higher sensory nerves, and his object has been to determine experi- 
mentally what parts can be physiologically called a brain in the Inverte- 
brates. This is shown to be the case with the supra-oesophageal ganglion 
of Crustacea and Tracheata, but not of Annelids, whose dorsal ganglion 
is a sensory but not a motor centre. Similarly in Nemertines andPlana- 
rians the dorsal ganglion is a sensory centre. In Molluscs the term 
brain is inapplicable, but the dorsal ganglion of Octopus (without which 
the animal does not feed itself or move voluntarily) is comparable to the 
Vertebrate cerebrum. In Appendiculariae, Echinoderma, and Coelentera, 
there is no part that can be called a brain. The cerebrum of Octopus 
* Quart. Journ. Micr. Sci., xli. (1898) pp. 391-431 (2 pis.). 
f ‘ Die Funktionen des Centralnervensystem uud ihre Phylogenese,’ iii. Abth., 
Braunschweig, 1898. See Biol. Centralbl., xviii. (1898) pp. 749-51. 
