Morpliolocjii of the Echinoidea. 67 



pedicellarife. Presenting the general appearance of one of tlie 

 pedicellariae so well described by Sladen (Ann. & Mag. Nat. 

 Hist. August 1880, p. 101, pis. xii. and xiii.), but without 

 the glands around the long stem, without any calcareous 

 valves within the lobed structures, and without any protrusion 

 of calcareous nature through the large foramen, the simplest 

 examination enables the histological elements described by 

 Dr. Haniann to be seen. As Dr. Hamann has stated, there 

 is the outer epithelial coat, and beneath it connective tissue 

 with C-shaped spicules, with, so far as I could see, but 

 few nerve-fibres, and the close layer of muscular fibres noticed 

 by Dr. Haniann. The mucus-gland layer, with its nucleated 

 cells and granules, is largely developed. In one happy, thin, 

 transverse section the remains of a partition, partly bisecting 

 the mass vertically, was evident. The head of the " organ " 

 obviously consists of three great mucus-glands united at their 

 bases and free above, and the opening is surrounded by a 

 sphincter. It is but just that 1 should state that, although 

 these special gland-sacs on stems have been discovered and 

 doubtless will be admirably described by Dr. Hamann, the 

 morphology of the gland-sacs and their coverings was 

 familiar to me, for it is the same as that seen in the 

 pedicellarife which formed the subject of Sladen's essay, 

 the distinction between the two kinds of organs being of 

 course the presence of the calcareous valves and the tactile 

 cushion and the less globular shape of the pedicellariai, which, 

 moreover, invariably have three glands around the long stem. 



In some of the bodies which one would have considered to 

 be Dr. Hamann's organs without doubt, I found exceedingly 

 atrophied calcareous valves in the tumid '' Drilsenhallen.'" 

 The valves were very reticulate and delicate in the extreme ; 

 but the sharp points and the relics of the curved basal parts 

 remained. The gland-structure was that described by Dr. 

 Hamann, and there were no tactile cushions to be seen. The 

 foramen was large and had the usual sphincter ; there were 

 no glands around the short stem. 



1 must confess that this finding of an atrophied series of 

 valves, whilst it indicates the direction in which the nature of 

 the new organs should be sought, also diminishes the interest 

 one felt disposed to take in them. It must be remembered 

 that Sladen distinctly states (op. cit. p. 108) that the pedi- 

 cellariai globiferaj ( = gemmiformes) give forth mucus, and he 

 described their glands. Hence it is correct to state that in 

 function the organs just discovered and the long and valve- 

 headed pedicellarias are partly similar ; the latter, being the 

 more highly organized, have a clasping and tactile power, 



6* 



