308 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



covered with very slender, hair-like spines ; secondaries and miliaries 1-3 mm. 

 long and primaries up to 9 or 10 mm. in length ; primaries, however, not con- 

 spicuously different or sharply distinguishable from secondaries. — Color of test 

 pale purple, almost a grayish lavender, darkest in posterior dorsal interambula- 

 crum and in band of subanal fasciole ; spines silvery white. 



2 specimens, Sagami Bay (35° 11' N. x 139° 45' E.), Japan, 50 fathoms.— 

 1 specimen, Sagami Bay (35° 3' N. X 138° 48' E.), Japan. Owston collection. 



List of the species of Spatangus 



purpureus O. F. Miiller, 1776. Zool. Dan., p. 236. Norway to Azores, and in 



Mediterranean, 5-458 fathoms, 

 raschi Loven, 1869. Ofv. Vet. Akad. Forh. Stockholm, p. 733. Norway to Azores, 



100-805 fathoms, 

 liitkeni A. Agassiz, 1872. Bull. Mus. Comp. Zool., 3, p. 57. Japan, littoral (?)- 



107 fathoms; Moluccas (Sluiter). 

 capensis Doderlein, 1905. Zool. Anz., 28, p. 624. South Africa, 40-280 fathoms, 

 paucituberculatus A. Agassiz & Clark, 1907. Bull. Mus. Comp. Zool., 50, p. 253. 



Hawaii, 127-286 fathoms, 

 altus Mortensen, 1907. " Ingolf " Ech., pt. 2, p. 131. " China Seas." 



Key to the species of Spatangus. 



Primary tubercles of dorsal side numerous, 150 or more in lateral and posterior 

 interambulacra together. 

 Subanal fascioled area more than twice as wide as high with a reentering angle 



on upper side purpureus. 



Subanal fascioled area not nearly twice as wide as high, with no reentering 



angle. 



Only 2 pairs of ambulacral pores included within subanal fasciole on each side; 



anterior petals tapering towards ends, more or less decidedly so proximally. 



Primary tubercles present in ambulacra between end of petals and ambitus ; 



width of posterior petals less than one-fourth length raschi. 



Primary tubercles wanting in ambulacra ; width of posterior petals more 



than one-fourth length capensis. 



3 pairs of ambulacral pores included within subanal fasciole on each side ; 

 anterior petals broad, not tapering towards ends, even proximally altus. 



Primary tubercles of dorsal side few, less than 50 in lateral and posterior interam- 

 bulacra together. 

 Lateral ambulacra with two, one, or no primary tubercles ; test very broad and 

 flat, vertical diameter about equal to one-half length or less . paucituberculatus. 

 Lateral ambulacra with from six to twelve primary tubercles ; vertical diameter 

 usually more than half the length. 

 Plastron with little or no keel; subanal fasciole 1-1.5 mm. broad; color deep 



purple liitkeni. 



Plastron with conspicuous keel; subanal fasciole 1.5-2 mm. broad; color 

 grayish lavender pallidus. 



