45G 



18) Launoy, Contribution ä, I'^tude des ph^nomfenes nucl^aires de la 

 86cr6tion. These de Paris 1903. 



19) Scott, The Structure, Micro - Chemistry and Developn^ent of Nerve 

 Cells, with special Reference to their Nuclein Compounds. Univer- 

 sity of Toronto Studies. 



20) Felicine, Ueber die Beziehung zwischen dem Blutgefäßsysteme und 

 den Zellen der Nebenniere. Arch. f. mikr. Anat., Bd. 63. 



Nachdruck verboten. 



Crayfish Spermatozoa. 



By E. A. Andrews, Baltimore. 

 With 7 Figures. 



The present notice deals chiefly with the anatomy of the sperms 

 of Cambarus affinis as made out in the spring and autumn of 1903 

 and the winter and spring of 1904. 



When the vas deferens is cut into short pieces upon a slide the 

 contents ooze out as milk-white, opaque, cylindrical rods of paste. 

 This dense, viscid paste is made of an outer part and a central axis, 

 so that it suggests maccaroni. The outer part is a clear matrix rend- 

 ered turbid by innumerable minuts droplets: the central axis is the 

 mass of sperms. An estimate of the number of sperms in both vasa 

 deferentia, when full, in the winter season, gave nearly 2000000. 



Each spermatozoon is a translucent highly refractive body some 

 8 J« in diameter and without any of the projecting radii commonly re- 

 garded as always evident. The spermatozoon is a flattened spheroid, 

 or a thick disk with rounded edges, and about one half as thick as 

 long. It is not quite circular but somewhat elliptical in outline. 



The most conspicuous part of the sperm is the well-known vesicle 

 that takes up about one half of the bulk of the sperm. This structure 



Fig. 1. Optical sections, lengthwise and transverse, of normal sperm as seen from 

 the sides. 



gives the sperm, as seen from above or from below, the appearance 

 of being chiefly two concentric elliptical rings. Side views, however, 

 as shown in Figure 1, make the character and relationships of the 

 vesicle intelligible. 



