224 REPORT OX THK PENNATULIDA. 



3.— Specimens with perfect stalks are very rare, but a certain 

 number have been obtained and described from various locahties. 



4. — Specimens with perfect tops appear, with the sole exception of 

 the Glasgow specimen drawn in Fiq 1 , to be absolutely unknown. At 

 any rate we have been unable to find any record of other specimens, 

 and Kolliker. who has made a special study of the whole group, ex- 

 pressly states that he does not know of the existence of any. 



Of these facts, acknowledged by all, no explanation has, so far 

 as we can ascertain, been attempted hitherto. Under these cir- 

 cumstances we would venture to submit the following considerations, 

 although from want of direct evidence we cannot yet offer a complete 

 explanaticn. In the first place it must be borne in mind that Virgularia 

 is found living alongside of two other closely allied and very similarly 

 constituted genera, viz., Funiculinn and Pennutuhi, and may even be 

 brought up at the same haul with one or other of these ; and yet while 

 the specimens of Virgularia are invariably broken, those of Funiculina 

 or Pennntida are as invariably immiitilated. The cause of the mutilation 

 is, therefore, to be sought for in some one or more of those points in 

 which Virgularia differs from the other two genera, and which in some 

 way or other determine that it shall be broken, while the allied forms 

 remain entire. 



Now the chief points of contrast between Virgularia on the one 

 hand, and Funirulinn and Pninatula on the other, are^ 



1. — The great brittleness of the stem of Virgularia. and the fact 

 that, instead of tapering upwards to a fine flexible point, it remains of 

 considerable thickness up to the very top of the rachis. 



2. — The length of the stalk in Virgularia, and its strongly marked 

 hook-like termination. The stalk is much longer relatively than that 

 of Fu)iicuUna, and is much longer absolutely than that of Pennntula. 



We Icnou; from the observations of Rumph and Darwin, to be 

 noticed further on, that Virgularia lives with the stalk planted in the 

 sea bottom, and the rachis freely projecting above it ; and from an 

 observation of Captain Lancaster's* it appears to require a tolerably 

 firm pull to draw oxit a Virgularia from its hole. 



We would therefore suggest that the fracture at the lower end is 

 caused at the time of capture, and is due partly to the brittleness of 

 the stem, and partly to the firm implanting of the stalk in the sea 

 bottom. The usual site of the fracture — at the junction of rachis and 

 stalk (ride Fig. 1) — strongly supports this view, for while on the one 

 hand the dredge dragging along the bottom would snap off the stem 

 exactly at this point, on the other the tangles brushing against the 

 rachis higher up would beud and break it at the very same spot, i.e., 

 its point of emergence from the ground. Knowing as we do that 

 Virgularia when living undisturbed not only has the stalk, which is 

 wanting in almost all dredged specimens, but also that the stalk is buried 



* Kerr's " Collection of Voyages," vol. viii., p. 119. Quoted in Darwin's 

 " Naturalist's Voyage round the World." 



