PENNATULA PHOSPHOREA. 29 



These polypes are arranged in transverse rows along each side of 

 the rachis, the several polypes of each i"ow being fused together along 

 nearly their whole length, so as to form broad horizontal leaven (Figs. 

 1, 2, and 3 dl), projecting out at right angles to the rachis. The 

 presence of these leaves forms the most marked point of difference 

 between Pemtatula and Fiiniculina, in which latter each polype is 

 quite free from its neighbours and inserted independently into the 

 rachis. 



As in Fuiticulhia the polypes are placed along the dorsal and 

 lateral surfaces of the rachis, but not on the ventral surface (Figs. 2 

 and 8), which, however, unlike Funiculina, is thickly studded with 

 zooids (Figs. 2 and 8, c). 



As shown in Figs. 1 and 2 the leaves are not all of equal length ; 

 the longest ones, in the female specimen, are at about one-third 

 of the length of the rachis above its commencement, from 

 which point they diminish gradually in length towards the upper 

 end of the rachis, and much more rapidly towards the lower end. The 

 number of polypes composing the leaves varies according to the length 

 of the leaf ; th 3 greatest number, found in the longest leaves, being 

 twelve in the f jmale specimen (Fig. 3 d), and in the male fifteen ; while 

 the topmost leaves consist of three or even only two polypes each. 



The rachis and leaves are of a deep red colour, due, not to the 

 fleshy body-substance which is nearly colourless, but to red calcareous 

 spicules which are present in immense numbers throughout these 

 portions of the Pen (Figs. 8, 4, and -3 /). The stalk is much paler, the 

 spicules in it being colourless. 



Anatomical Desckiptiox. 

 1. — The Stalk and RacJii^. — 



Thestalk (Figs. 1, 2, 3) which forms about 2-5thsof the entire length 

 of the Pen, is cNiindrical. with a diameter in the female specimen of 

 0-21in. along the greater part of its length. The bottom third is 

 somewhat dilated and bulbous, and the upper end, just at the junction 

 of stalk and rachis, slightly constricted, forming as in Funiculina 

 the narrowest portion of the stalk. 



As the Oban specimens were destined for museum purposes we 

 have been unable to investigate the structure of the stalk in them, and 

 the following account is based on a series of preparations made from 

 a couple of specimens in the Owens College Museum, obtained from 

 Naples. 



The stalk is really a tube, being traversed along its whole length 

 by an axial canal, whose diameter along the greater part of the length 

 is about half that of the stalk itself, somewhat exceeding this in the 

 upper and lower thirds, and being rather smaller in the middle third. At 

 the bottom of the stalk this canal is said by KoUiker to open to the 

 exterior by a minute orifice, the existence of which we have, however, 

 been unable to confirm. 



