Fewkes.] 
204 
March 6, 
“ Sehr eigenthiimlich verhalt sich das Deckstiick bei starkerer 
Beriihrung, insofern auf einen Reiz hinzuerst in der Umgebung der 
beiden hornformigen Canale des Olebelialters und spaterhin auch 
von den Ecken beginnend in dergesamraten Gallerte eine weissliche 
Truburg auftritt. Dieselbe beruht auf dern Erscheinen ausseror- 
dentlicb feiner Kornchen, die wieder (nach etwa einer halben 
Stunde) verschwinden, wenn die Eudoxie der Ruhe uberlassen wird. 
Die eigenthumlicheTrubung erinnert an eine analoger Ersclieinung 
bei Hippopodius. 
Nurdass hier auf einer Reizerfolgende und spater verschwindende 
milchige Farbu^g an die Ektodermzellen der Schwimmglocken 
gebunden ist. In gewissem Sinne muss selbst die structurlose 
Gallerte des Deckstuckes einem Reize zuganglich sein, wie das 
allmahliche Auftauchen und ebenso langsame Verschwinden einer 
ziemlich intensiven Triibung beweist.” 
We might possibly compare this phenomenon with the cutaneous 
circulation and change of color in pelagic fish embryos and in Ceph- 
alopoda, but as we know so little of the organs by which it is pro- 
duced that one can as yet hardly venture an explanation. 
The excretion and discharge of a colored fluid from those organs 
which are known as “ cystons ” or tasters with a terminal opening, 
has been noticed by several authors. Both Kolliker and Leuckart 
speak of it, although they seem to regard the discharge as due to 
a rupture of the wall rather than through a normal terminal open- 
ing. Kolliker says, “Ohne Zweifel ist diese Substanz ein Excretion- 
stoff, doch wird ohne genauer Kenntniss ihrer chemischen Besch- 
affenheit nichts Naheres uberihre Bedeutung beizubringen sein.” 
Haeckel describes the structure of these Cystons or “anal vesicles” 
showing that they are excretory organs, with a terminal anus and 
glandular walls often highly colored. They are according to him 
confined to the Physophores, mainly to the Apolemidse, Agalmidae 
and Forskalidse. 
The “cystons” or hydrocysts, with “mouths” in the Agalmi- 
dae are often, according to Haeckel (op. cit. p. 219), colored red 
or brown, and “the fluid secretion, or the pigmented granular or crys- 
talline masses secreted by it, are ejected by the distal mouth, or 
rather the anal opening, which is closed by a muscular sphincter.” 
In the genus Forskalia the same author says, “ When a quietly 
floating Forskalia is touched, it suddenly discharges the contents 
of the chromadenia [pigment glands] and makes the surrounding 
water dark and intransparent.” 
