ECHINOIDEA. I. 65 



scattered, and form no regular series; the areoles of a middle size; no great difference between the 

 actinal and the abactinal sides. The spicules irregular fenestrated piates, not in series; the tube feet 

 in one irregular series on the actinal side; no sucking disk. Three kinds of pedicellariæ: ophice- 

 phalous, tridentate, and triphyllous ones. The ophicephalous ones with the valves highly constricted 

 in the middle, short neck, and tube-formed stalk. The tridentate ones occur in two forms, a larger 

 one with leaf-shaped point, filled by a coarse, thorny net of meshes, not involuted; and a smaller one, 

 simply leaf-shaped, with the widenings of the apophysis ending at the very edge of the blade. The 

 stalk of the tridentate and the triphyllous pedicellariæ of the common structure. 



Species : T. Koehleri n. sp. 



Distribution: The Davis Strait. — Abyssal form. 



Sperosoma Koehler. 



The primary spines on the actinal side curved, with a large white hoof; they occur scattered; 

 the areoles large. Rather great difference between the actinal and the abactinal sides. The secondary 

 ambulacral piates on the actinal side of the same size as the primary ones; the ambulacral areas con- 

 sist on the actinal side of 8 series of piates. The tube feet on the actinal side in three widely 

 separated series. The spicules large, fenestrated piates, not arranged in series; sucking disk well 

 developed. Only tridentate and triphyllous pedicellariæ. The tridentate ones are simply leaf-shaped; 

 the widenings from the upper end of the apophysis do not reach to the edge of the blade; in the large 

 ones the blade is filled by a coarse, thorny net of meshes. The stalk of the common structure. 



Species: Sp. Griiualdii Koehler, biscriatuiii Doderlein. 



Distribution: The northern Atlantic, the Indian Ocean. — Archibenthal forms. 



Kamptosoma n. g. 



The spines (at all events some of them) flat and widened towards the point; hoof (?); no great 

 difference between the actinal and the abactinal sides. Secondary ambulacral piates seem to be wanting. 

 The tube feet form a single series. Only tridentate and triphyllous pedicellariæ; in the tridentate ones 

 the blade is flat with more or less developed cover-plate; a larger and a smaller form are found, only 

 little different. In the triphyllous pedicellariæ the cover-plate is uncommonly slightly developed. The 

 stalk consists of long threads almost only united at the ends. 



Species : K. astrrias (A. Agass.). 



Distribution: The Pacific. — Abyssal form. 



IiLccrtæ scdis: 

 PlioriHosoma paiiamensc A. Ag. 



— Jiispiduvi A. Ag. 

 Astlicnosoina longispinuni Yoshiwara. 



— lijamai Yoshiwara. 



.\s has been done above in the Cidarids I shall also here expressly observe that I do not 

 regard the generic diagnoses given here as complete. As well the structure of the test as the inner 

 anatomy stands in need of an exact examination in several of the genera. I must, however, regard 



The Ingolf-Expedition. IV. i. q 



