444 PELMATOZOA. 



joints of which are dice-box-shaped. The genus has therefore been 

 compared to an Antedon with a Bourgueticri?ius stem. 



Family n. Saccocomidtz. — This remarkable family comprises only 

 the single genus Saccocoma, which is represented by one species 

 (S. pectinata, fig. 317) only, from the Upper Jurassic rocks (Litho- 



Fig. 317.— Saccocoma pectinata, from the Upper Jurassic of Bavaria. The left-hand figure 

 shows the complete organism, with the arms inrolled. 



graphic Slates) of Bavaria. In this singular genus, the organism is 

 free, the larval peduncle being evanescent. The calyx is composed 

 of a single minute basal supporting a cycle of five, thin, closely 

 united radials, ornamented externally with ten radiating ribs, 

 and the ventral surface is occupied by five oral plates. There are 



