90 Mr. Toulmin Smith on the Ventriculidse 



have distinct heads — which heads are perfectly smooth and re- 

 gular in general form, and with no deep anfractuosities, instead of 

 being, as the contractile theory requires, most of all convoluted. 

 Finally, I shall presently show that there was a special and most 

 beautiful provision in the intimate structure of these animals 

 against contractility either voluntary or by ordinary accident. 



Nor is there any want of examples of the presence of similar 

 convolutions without contractility in what I hope to show to be 

 kindred zoophytes of the present day. The Eschar a foliacea is 

 familiar to every one. But I am indebted to the kindness of 

 Professor Owen for a still more striking illustration of this ar- 

 rangement in a recent zoophyte. That gentleman a short time 

 ago placed in my hands, with the liberal permission to examine 

 it in any mode I chose, a specimen of Meandrina recently brought 

 from the Indian Ocean, and which had been treated with mu- 

 riatic acid. All the calcareous parts being thus dissolved, there 

 remained only the soft animal parts. I observed with much 

 gratification that these consisted, in fact, of a single membrane 

 folded up almost exactly after the manner of some of the more 

 irregular of the Ventriculites — very much indeed like the Ventri- 

 culites radiatus described by Mantell and others as having an 

 " integument formed of cylindrical fibres anastomosing," &c. 



However much differing in the complexity and mode of the 

 convolution of its membrane, the body of every member of the 

 family of Ventriculidse appears to have had an opening at its 

 upper part, and that body approached more or less to the form of 

 an inverted cone. They usually grew single. In one or two 

 species they are grouped, and there are occasional instances, but 

 very rare, of double specimens of those whose usual habit is single 

 — just as we occasionally find a double Actinia. 



Having thus shown the general character and habit of the body 

 of these animals, I next proceed to show the nature of the root. 



The attention of Ellis was particularly attracted, in describing 

 his Corallines, to one variety, the Corallina astaci corniculorum 

 cemula as he calls it, or Lobster's Horn coralline, as having roots 

 very different from those of ordinary corallines, " which rise up 

 from an irregular mass matted together to form the stem*." The 

 roots of this zoophyte, on the contrary, " regularly enter in in 

 whirls round the joints ;" the body of the animal, according to his 

 figure, tapering off to a point in the midst of these root fibres f. 



Something after such a type was the habit of the roots of the 

 Ventriculidse. They were not, as described by Dr. Mantell, de- 



* Ellis's Corallines, p. 16 and pi. 9. B. 



\ This peculiarity is not marked either in the description (p. 86, 2nd ed.) 

 or figure (pi. 19) of Dr. Johnston ; but the figures and descriptions of Ellis 

 are seldom unworthy of dependence. 



