90 THREE CRUISES OF THE “BLAKE.” 
fan-shaped spines, it would have been unhesitatingly placed in 
the genus Dorocidaris. If the isolated huge fan-shaped radioles 
Fig. 349. — Dorocidaris Blakei. 2. 
nearly identical in shape with those of the jurassic Rhabdoci- 
daris had alone been collected, few palseontologists would have 
hesitated to refer them to that genus. 
Another interesting type of deep-sea Cidaride allied to ter- 
tiary forms is Porocidaris (Fig. 350), which is characterized by 
the peculiar serrated spines found near the mouth. 
We first dredged off Havana, and subsequently in all parts of 
the Caribbean, a fine species of Salenia (Fig. 351), a genus once 
very common in the jurassic and cretaceous seas. The first 
living species of the genus (Fig. 352) was dredged by Pourtalès 
Fig. 352. — Salenia varispina. 4. 
off Double-headed Shot Key, in 315 fathoms. The “ Blake" 
found it to be a characteristic species of the Caribbean abyssal 
fauna. This genus is characterized by the présence of a large 
