CHAKACTERISTIC DEEP-SEA TYPES. CRUSTACEA. 43 



pletely fill deep orbital sinuses in the front of the carapace in 

 which they are imbedded. The Willemcesiae have a very wide 

 geographical distribution, and they are peculiarly adapted for 

 burrowing in soft ooze, in which they seem to live. Some of 

 the species are wonderfully transparent. They are the repre- 



Fig. 238. Munida. 1. (S. I. Smith.) 



sentatives in our seas of the fossil Eryonidae, which flourished 

 in the Jurassic lithographic beds of Solenhofen, in Bavaria. It 

 is interesting to note that the eyes of the fossil species were 

 extraordinarily developed. 



Nephropsis Agassizii (Fig. 240), the only species of Astacidea 

 discovered, belongs to a genus previously known only from a 

 single imperfect specimen dredged in the Bay of Bengal. The 



