222 



J. H. OKTON. 



This figure is a drawing of a tube-foot of a specimen of C. nonnani 5-3 cm. 

 long, taken from the right ventral ambulacral row — as was that of C. 

 saxicola, shown in Fig. 6, p. 221. A comparison of these two figures, 

 which may be regarded as typical, indicates the differences which occur 

 in the podial spicules of these two forms. Those in C. saxicola are rela- 

 tively few, mostly straight, with foramina in a single series, although 

 there may be spicules with more than one series. Those in C normani, 

 on the other hand, are mostly broadly V-shaped, with foramina in two 

 or more series : some spicules, however, are straight, with foramina in 

 single series, as in C. saxicola. There are also a few bell-shaped surface 

 spicules around the base of the tube-foot. 



The difference in the relative number of spicules in these two forms 



Fig. 7. — A single tube-foot of C. normani, showing the kind and number of the podial 

 spicules (x about 65).'' 



is also well shown in these figures, and this difference is emphasized still 

 more by the fact that not all the spicules in the tube-foot of C. normani 

 could be drawn. 



DISCUSSION OF SOME FORMEK OBSERVATIONS ON 

 C. SAXICOLA AND C. NORMANI. 



The establishment of undoubted specific and differential characters — 

 given in the preceding pages — for these two species enables a partial 

 clearing up to be made of the literature referring to these forms. Norman 

 (3) in 1893 described three specimens. A, B, and C, of Cucumaria obtained 

 at Polperro in 1865 as C. montagui. Subsequently Pace (1) in 1904 

 showed that one of Norman's specimens, A, was undoubtedly the same 



