CHAP. XVI.] 



RADIAL SERIES : PEDICELLARI^E. 



429 



There were therefore 1735 normals, 19 symmetrical varieties and 9 

 irregulars. It will be noted not only that the symmetrical varieties 

 are comparatively frequent, but also that the several forms of irregu- 

 larity were seen for the most part in single specimens only. 



II. PEDICELLARI^I OF ECHINODERMS. 



The number of jaws in the pedicellariae differs in different 

 forms of Echinoderms, and I am indebted to Professor C. STEWART 

 for information concerning them. 



In Asteroidea the number of jaws is usually two, but in Luidia 

 savir/nii the normal number of jaws is three. 



In the Echinoidea the number of jaws is usually three, but 

 in Asthenosoma the normal number is four. 

 638. Dorocidaris papillata : number of jaws in pedicellarise 



I I 



FIG. 129. Pedicellarise of Dorocidaris papillata. 



I. Normal form with three jaws. 



II. A pedicellaria with four jaws from the abactinal region. 



(From Prof. STEWART'S specimens.) 



normally three as in Fig. 129, I, but occasionally four in pedi- 

 cellariae of the abactinal region, as in Fig. 129, II. [Note that the 

 variety is perfect and symmetrical] For this fact I am obliged to 

 Professor Stewart, who kindly allowed this figure to be made from 

 his preparations. 



639. Luidia ciliaris : pedicellariae nearly all with three jams; but 

 on Roscoff specimens a few having two jaws occur on the borders 

 of the ambulacral groove. In BanyuTs specimens none such were 

 found in this position, but there is one in almost all the marginal 

 intervals. CUENOT, Arch. zool. exp., S. 2. V. bis, p. 18. 



640. Asterias glacialis : occasionally three- jawed pedicellarue like 

 those of Luidia are found among the normal two-jawed pedi- 

 cellarise. CUENOT, 1. c., p. 23. 



