160 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
same investigator, spermatopliores were first seen in Eupagurus by Scliwammerdam 
in 1752, and were observed in the Brachyura also by Cavolini in 1792. They were 
rediscovered by Kolliker in 1841. 
SPERM CELLS. 
The sperm cells of the lobster were apparently seen for the first time by Valentin, 
in September, 1837 ( 192 ), and he gave a brief account of his discovery in the following 
year. A more accurate account by Kolliker, who also remarked on the apparent 
immobility of the “ rayed cells,” appeared in 1843 (109). 
The structure and genesis of the spermatozoa of the lobster have been studied 
with much detail by Grobben (83), Gilson (77), Hermann (89), and more recently by 
Sabatier (173). 
Each sperm cell (fig. 129, plate 37) consists of a cylindrical and partially hollow 
column or shaft, surmounted with a rounded dome, on what may be called the superior 
end. Between the capital and shaft three long, slender processes are given off, making 
an angle of 120° with each other. The processes are sharp-pointed, rigid, and very 
slender. The stiffness of the rays has led to the erroneous view that the rayed con- 
dition represented an immature stage in the maturation of the cell. The sperm cells 
withdrawn from the spermatic receptacle where they have lain weeks or months are 
still rayed, although the processes are often broken off or very limp (fig. 129, a). 
Apropos to this subject Grobben (83) says: 
The stiffness of the rays does not prove that these cells are completely immobile. Moreover, 
the observation of Owsjannikow that the rays sometimes draw themselves in, and certain structures 
which Ihave examined, enableme to conclude definitely that these rays are liviug protoplasm and that 
they represent amoeboid processes, remaiuiug almost in a state of rest. [Compare the observation 
of Cano quoted ou p. 49.] 
The genesis of the sperm cells from the spermatoblasts has been satisfactorily 
determined in most particulars, but there are some questious, which concern both this 
and the structure of the adult sperm cell, which are still undecided. The conclusion of 
Sabatier that the rayed cells become enucleated in the course of their growth can 
hardly be accepted. Sabatier has suggested that the stiff rays may serve at first to 
stick the cells together. 
Nothing is definitely known either as to how the spermatopliores are conveyed to 
the seminal receptacle or how the spermatozoa reach the eggs and fertilize them. 
