ASTEROIDEA 



107 



sometimes an angle instead of a curve at the interradial plate (Koehler, XII, 9 and 10). 

 The superomarginal plates run as high as 17 and are conspicuously broad, or only 

 sUghtly broader than long. The best figure oi penicillatus is that of Sladen (LVII, 5) in 

 which the shape is broadly stellate and the superomarginals rather narrow. Ludwig's 

 (1905, pi. 5, fig. 4) figure of penicillatus is of a very young specimen (R 4 mm.) and 

 useless for estimating the appearance of the adult. His figures oi grayi (pi. 5, figs. 6-9) 

 represent the two varieties illustrated by Koehler, but at a younger stage. 



There are other major variations not illustrated. On the assumption that grayi is 

 represented by the pentagonal specimens with fewer superomarginals, and penicillatus 

 by examples of a stellate shape with more numerous superomarginals, the following 

 analytical table was made of all except very young examples. The columns are to be 

 read from top to bottom. The specimens are arranged in columns A-G in groups 

 according to the number of superomarginals to a ray (excluding interradial plate). The 

 third, fourth, fifth transverse columns attempt to differentiate form of body. Stellato- 

 pentagonal indicates that there is a broad angle at the interradius as in Koehler's fig. XI, 

 9, while the side of the ray is fairly straight. The breadth of the ray at interradius must 

 be greater that its length measured along the side. In stellate specimens (transverse 

 column 5) the two dimensions are equal or the length is the greater (Sladen, LVII, 5). 



1 Three young penicillatus, R 13-14 mm., Sts. WS 81, 871. 



2 Largest arcuate pentagonal, R 23 mm., St. WS 85 ; 3 forma penicillatus, 4 f. grayi. 



3 See notes; contains intermediate forms. 



* Four forma penicillatus and 3 broad-margined intergrades or stellate f. grayi. 



5 One forma grayi and 2 intergrades or stellate f. grayi. 



6 None of these is typical grayi; i (St. WS 248) is the heavy margined substellate form of grayi. The 

 largest, R 42 mm., has 3 teeth. 



' Sts. WS 225, 248; not typicsl grayi. 



* Includes the 3 not typical ^rajyt; i (orma penicillatus, 1 intermediate. 

 ' Three similar to pilulatus of Sladen ; i aberrant. 



1" St. WS 848, R 50 mm., r 25 mm., R = 2r, {orma penicillatus. 



11 St. WS 98, R 42 mm., r 22 mm.; superomarginals about as broad as in Sladen's figure of pilulatus. 



