4 ON THE ECHINODERMATA OF THE 



Premature Form. In early stages of growth the body is much more pentagonal 

 in fonn and usually lighter in colour, which not unfrequently approaches a pinkish or 

 flesh tint. The ambulacral sucker-feet are well spaced and arranged in single almost 

 straight lines. In a small specimen 9 millims. in length the two dorsal ambulacral 

 series are not so fully developed as the three ventral ; they contain fewer suckers ; and 

 these are arranged in an almost straight line, except at the extremities, where the zigzag 

 alternating character of the series is clearly manifest. The oral tentacles, although 

 only partially extended in the specimen under notice, are already thick, frondose, and 

 many times divided, whilst the body-skin is filled with regularly-spaced calcareous 

 spicules roundish in form and punctured with holes, the solid interspaces being broader 

 than the apertures. Comparing this individual with another somewhat larger, 20 

 millims. in length, it will be noted that the body is proportionately more elongate, the 

 ambulacral feet more numerous, and now arranged distinctly in double rows of alter- 

 nating suckers. The tentacular plume is slightly fuller, but still exactly the same in 

 general character as in the earlier stage ; in fact the changes above noted are the only 

 conspicuous accompaniments of increased size perceptible to the naked eye. On micro- 

 scopic examination, however, of the larger specimen it is found that no spicules are 

 present in the skin ; and this is a feature which at once constitutes the most striking 

 difference between the two stages of growth. Such a circumstance is very remarkable ; 

 and although we are unable to say, with the limited amount of material at our disposal, 

 whether this is a state of things which always obtains, at least two other individuals, of 

 succeeding and still premature stages of growth, are equally wanting in spicules a 

 character which, as previously observed, is not unfrequent in the adult form of 

 C. frondosa. 



It is noteworthy that the features presented by the young specimen of 9 millims. 

 accord exactly with those given by Liitken as characterizing C. minuta, Fabr. (excepting, 

 we imagine, the tentacles); but on this point Liitken does not say much, as these organs 

 were only partially extended in his specimen. If the view, therefore, which is here 

 taken be correct, it would lead naturally to the deduction that C. minuta is nothing 

 more than the young of C. frondosa. Before this can be definitely asserted, however, 

 the examination of the growth-phases in a greater number of examples of the present 

 species would be desirable ; still we feel bound to say, after a very careful study of all 

 the available material, that we are unable to separate the young form above described 

 from the series of undoubted C. frondosa, the only feature in which it differs altogether 

 from the older stages being the presence of the calcareous bodies in the integument. 



From the description given, it would seem that the Holothuroid named by Forbes 

 and Goodsir C. fucicola is a young form of the present species, a determination now 

 generally concurred in by most naturalists. 



Variations. Amongst the list of synonyma will be found Rotliryodactyla grandis, 

 Ayres, which we have been led to include rather from a diffidence against dissenting from 

 the opinion of so many eminent writers upon Holothuroids than from personal conviction. 

 Indeed there would seem to be great doubt about the absolute identity of this form ; 

 for, although the main characters recited in the cursory description accord well enough 



