a22 GEOFFREY SMITH. 
have very characteristic forms, which are depicted in text- 
figs. 3, 80, 31, 32, 33, 55, 58, 61. 
It will be noted that the uropods and telson of Paranas- 
pides are more elongated than in the other genera, in 
correlation with the swimming mode of life. 
Special attention must be called to the close correspondence 
between the uropods of Preanaspides (text-fig. 3) and 
Anaspides (text-fig. 50), even individual sete, e.g. those 
TEXT-FIG. 31. 
Paranaspides lacustris. Telson and wropods. 
on the outer border of the exopodites, being practically 
identical in the two cases. The short sete also upon the 
margin of the last two segments in Anaspides and 
Paranaspides are also represented in the fossil. The 
detailed correspondence in these and the other limbs of 
Anaspides, Paranaspides and Prweanaspides permits 
us to place them with confidence in the same family. The 
uropods and telson of Gampsonyx, Paleocaris and 
Gasocaris agree on the whole very accurately with the 
