Spermatophores in Panulirus and Paribacus. 189 
picks comparable to the setae on the thumb of the female claws 
above discussed. From such a beginning, that is some special sets 
of setae concerned with cleansing, might have arisen special ele- 
vations to bear these setae and thus have come about a more and 
more complete forceps. 
The eleansing function amongst erustacea deserves more attention 
than is usually given it, for whenever an animal is accustomed to 
explore more or less of its entire outside surface the stimulation thus 
produced should have a fundamental effect upon the functioning of 
its central nervous system. 
In crustacea especially where the exploring limbs are armed 
with setae having nerve ends at the bottom and where the shell 
however inert is yet pierced with setae of like nature, the animal 
must have a large external environment which is really of its own 
causation, that is to say, the stimuli which are received through its 
cleansing organs and the stimuli received through the regions of the 
body surface that are cleansed and explored should, in the central 
nervous system make changes that might be permanent and add 
largely to the equipment of the animal in giving it a more exact 
knowledge of the boundaries of its own body agains the larger out- 
side universe, 
That these cleansing movements are wide spread is indicated 
by the recent observations of GIESBRECHT (3) and of Dorreıs (4) on 
certain Stomatopods and Shrimps. 
In Sqwilla mantis GiESBRECHT describes elaborate cleansing 
habits with use of specialized, elongated, maxillipeds and definite 
posturings of the body. The first pair of maxillipeds, the “Putz- 
beine” is used only for eleansing and bears a small claw with rasp, 
saw and other special setae. In Leander ziphias DorLEın describes 
complex actions in which the small cleaning claws of the first limbs 
are used not only to pull off dirt but, when closed, as brushes that 
brush the mouth parts like a tooth brush, the antennae and eyes, 
the tail and even the gills, as may be seen in these translucent 
shrimps. DorLEın also emphasizes the existence here of special setae 
along these limbs at the joints, so placed that when the segments 
bend on one another the setae will be more or less pressed or pulled. 
These he calls “Stellungshaare” and assumes to be of great importance 
in giving stimuli to the animal that may regulate its movements, 
for he thinks that not only muscle stimuli but stimuli from these 
