CAULOPHACUS LOTIFOLIUM. 93 



together, the checker-like arrangement of parataugentials totally 

 disappearing. Lower down on the stalk, where the parenchynialia 

 have undergone ankylosis, the hexactinic pinnies gradually pass 

 over into a peculiarly modified, pentactinic form, in which the 

 suppressed pi'oximal ray is however frequently indicated Ijy a small 

 prominence (figs. 9-11). The persisting rays are much thicker 

 than the corresponding rays in a normal pinule of the body, 

 and what at once strikes the eye is the greatly swollen state of 

 the unpaired free ray, especially at its distal end. In this way 

 that ray acquires a club-like, or more generally a balloon-like, 

 shape. The swollen end is densely covered with short but stout, 

 conical tubercles, which become less numerous below on the 

 stalk-like part of the ray, finally to disappear altogether at the 

 base of that part. The terminal globular knobs often measure 

 9'3 !'■ in diameter, but are of various sizes leading down to a 

 club-like shape of 35 ,« breadth. In surface view under a low 

 power of the microscope (fig. 20), the dermal coating of the 

 stalk appears as if consisting of rongh- surfaced spherules closely 

 crowded together. A similar change in the character of dermalia 

 on the stalk has been known in Caulophacus elegans F. E. ScH. 

 ('87) and a agassizl F. E. Sch. ('99, p. 39). 



The gadraUa (figs. 2, 21) are likewise hexactinic pinnies ; 

 rarely pentactinic, the aborted distal ray being represented by a 

 mere knob. The free pinular ray, compared with the same of 

 normal dermalia, is much longer and proportionally more slender. 

 It is 220-300 />« long and about 30/^ broad as measuied across 

 from tip to tip of the strongest lateral spines in about the middle 

 of the ray. The axial rhachis, about 12/^ thick at base, gradually 

 tapers towaids the sharply pointed free end. The five remain- 



