3i6 
bulletin of the bureau of fisheries. 
By pressing the lips of the spermatic receptacle of a female with internal eggs 
nearly ripe, I have observed the sperm in a thick grayish mass which gave up its cells 
freely to sea water. This at all events suggests the possibility that the lobster herself 
is the direct agent in emptying her receptacle. In any case it is highly probable that 
the sperms are directed by chemotropism to the eggs after reaching the water. Nothing 
is known by direct observation of the phenomena of fertilization up to this point. 
What are the locomotor organs by which the sperms leave the sperm receptacle or 
by which they seek and find the eggs in the brood chamber? In our search for an 
answer to this question we must remember that the lobster lies upon her back when the 
eggs are laid, so that the force of gravity is a bar rather than a help to the movements 
of the sperm at this critical period. We may assume first that in leaving the receptacle 
the locomotor organs of the sperm cells are the rays or processes, which I showed in 1895 
to be rigid in the testes but limp in the receptaculum. This movement is probably 
amoeboid in character, consisting in the lengthening and shortening of the protoplasmic 
element of the process which flows from the neck of the cell. As with the amoeba a 
solid support is necessary for the process of locomotion to be effective, for according 
to a recent observer this animal probably draws itself along by the adhesion of its 
pseudopodia to the surface over which it creeps. 
How does the cell make its way through the water to the egg? No satisfactory 
answer can now be given, but if Bumpus was not entirely mistaken in his report of 
movements of the lobster’s sperm, as quoted above, we might plausibly suggest the fol- 
lowing solution, which is of course purely hypothetical. Upon reaching the water the 
plug of the capsule is loosened and falls out. Water then enters and fills the inner tube. 
This water is subsequently ejected by contraction of the vesicle, and the cell is drawn 
forward by inertia. It should be added here that in some forms ( Eupagurus ) the cap- 
sule is covered by a thin protoplasmic layer, and that in this membrane contractile fibers 
are sometimes seen; transverse rings can be demonstrated in the lobster. The action 
is supposedly recurrent. The processes direct the cell, as do barbs the arrow. The 
eggs are big targets, and the moment one is struck orientation of the sperm upon its 
surface begins. 
At this point speculation gives way in a measure to direct observation, and I return 
to the account of Koltzoff ( 172 ) who, like other observers, was unable to see the minute 
sperm enter the huge opaque egg. Disclaiming the ability to give a complete account 
of the movements of the sperm cells, he says: “My observations and experiments can 
naturally clear up only certain phases of these processes, and a whole string of hypo- 
thetical conclusions is needed to unite them into a harmonious whole.” 
Contact with a large and possibly moving body, or thigmotaxis, seemed to furnish 
the most powerful stimulus to the cell processes, which have been observed to shorten 
and lengthen, though not to the extent of more than one-tenth of their length. Once 
in touch with the egg the sperms begin to orient themselves in such a way that the cell 
comes to stand upon its thin elastic processes as upon a tripod, so that the head is placed 
in direct contact with the surface of the egg. The elastic process or processes in con- 
