76 Mr. Toulmin Smith on the Ventriculidse 



tinous?* : (2) external surface reticulated f '• (2) internal surface 

 covered with openings or perforated papillce : base imperforate, 

 (1) prolonged into a stirps, and (1) attached to other bodies." 



Of the characters thus described as generic I shall hereafter 

 show that all those which I have put in italics are erroneous ; 

 those marked (1) being altogether in opposition to the fact ; 

 those marked (2) being characters which are merely accidental 

 and non-essential. 



In describing these bodies in the above-cited paper Dr. Man- 

 tell says: — "The specimens which occur at Lewes, though gene- 

 rally considered as Alcyonia, do not entirely conform to the cha- 

 racters of that genus as given by modern writers ; yet they are 

 evidently very nearly allied to it. It is certain that the recent 

 animal possessed great powers of contraction and expansion which 

 enabled it to assume various dissimilar forms. In a quiescent 

 state it was more or less funnel-like ; when partly expanded cya- 

 thiform ; and when completely dilated it presented the figure 

 of a broad circular disc. To this versatility of shape is to be at- 

 tributed the great diversity of appearance observable in its reli- 

 quiae, whose forms must have been derived from the contracted 

 or expanded state of the original at the period of its introduction 

 into the mineral kingdom. That the animal enjoyed the power 

 of contraction and expansion above ascribed to it, will appear 

 evident from an investigation of its structure. The epidermis or 

 external coat is composed of fasciculi of muscular fibres, which, 

 arising from the pedicle, proceed in a radiated manner toward the 

 circumference, and, by frequently anastomosing, constitute a reti- 

 form plexus capable of dilating, lengthening and contracting, 

 according to the impressions it received J. The fasciculi are further 

 connected by lateral processes §, which increase the firmness and 

 coherence of the external integument. From the inner surface 



* This language and query show that the author had found no specimen 

 which enabled him to ascertain the actual internal structure. 



f The " reticulation " here meant was merely that of the " anastomosing 

 tubuli " named by Parkinson (8vo, p. 54), and has no reference whatever 

 to the beautiful reticulated fibrous structure hereafter to be described, and 

 which appears never to have come under Dr. Mantell's notice. If proof of 

 this remark were wanted, it is found as well in the extract which follows 

 from the paper in the ' Linnaean Transactions ' as in the specific description 

 given by him in the same page (South Downs, p. 168), where he speaks 

 of the " external integument composed of cylindrical, anastomosing fibres, 

 radiating from the centre to the circumference." 



\ Mr. Parkinson had already expressed a similar opinion as to some of 

 the fossils above named as figured by him. See ! Organic Remains/ vol. ii. 

 p. 145. 



§ These lateral processes are in reality the fibres going off to the polyp- 

 skin hereafter described. 



