458 REPORT—1890. 
Rabl, that in these typical vertebrates the mesoderm, as in Amphiowus and 
various lower animals, arises by what must be considered paired pouchings 
of the hypoblast (1) of the archenteron, (2) of the lip of the blastopore. 
I was much interested in being able to independently confirm this fact for 
Pristiwrus before I knew of the above-mentioned papers. 
In Pristiwrus the segmental duct as described by the later writers on 
Elasmobranchs, and as is the case in so many of the higher vertebrates, 
appears to arise almost if not entirely from the epiblast. 
Being at Naples, where Amphiozus is so plentiful, I naturally desired if 
possible to see something of its development ; but, though I had a large 
supply of the animals, I was unsuccessful, probably because, having other 
work on hand, I did not devote sufficient care to them, for another student 
was more fortunate. However, by mixing a quantity of their ova and 
spermatozoa, when naturally fertilised eggs seemed unattainable, I made 
a very small percentage of eggs go through the earlier stages of segmenta- 
tion. One or two of these eggs were interesting in that, from whatever 
cause, the process went on abnormally, segmentation being partial, as in a 
Teleostean. 
Turning, lastly, to the invertebrata, I had little time to examine, and 
have little space to describe, the wonders of the ‘ Auftrieb,’ or product 
of surface-skimming, supplied to me daily, with its swarms of copepods 
and other crustacea, especially the larve, with its salpe and medusa, 
pteropods, ctenophores, appendicularie and larve of worms, echinoderms, 
and other animals, and above all the beautiful compound hydrozoa. 
I was very glad to be able to see alive and at close quarters many animals 
that I had either never seen before or only as preserved specimens, and 
the occasional trips in the ‘ Johannes Miiller’ afforded opportunities for 
seeing these in their natural home, as well as for getting an idea of the 
life at the bottom. 
It may be worth while to mention a point of which I have seen no 
description with regard to a species of Lima that occurs here. This has 
the power of progressing by jumps like a Pecfen. Three specimens, how- 
ever, that I have kept for some time, partly in a round glass beaker and 
partly in a large tank about two feet square, in both cases with circulat- 
ing water, have each made for themselves what I can only describe as a 
house or tent, by closing in with a fairly dense network of byssus-like 
material some corner of the tank or a portion of the bottom of the 
beaker. Within this house the animal itself is free to move. In more 
than one case I have made the animal repeat this process, but have not 
been able to catch it in the act of spinning. Does the Lima do this to 
protect itself against foes or from being moved by currents of water, or 
is the byssus net to catch food, or are all these ends attained ? 
Lastly, it is hardly necessary for me to express an opinion on the 
structure and function of the Zoological Station, but it certainly is a 
great boon to have adjoining the room in which one’s work-table is 
situated another room which, while of moderate size, contains practically 
every work, periodical or other, that the biologist can require, and where 
the smallest pamphlet is clearly catalogued as soon as received. In fact, 
after all that has previously been said by more competent judges as to the 
admirable intelligence and precision with which the Station is worked 
throughout every department, I have only to thank the staff and all the 
workers therein for the ready kindness and civility that I have met with 
during my pleasant stay at Naples. 
ne. re 
