332 Mr. P. H. Carpenter on the Supposed 



unfortunate one, as being calculated to mislead. But, apart 

 from this question, there is a great difference between the two 

 pieces to which De Loriol gives this name in Tetracrinus and 

 in Apiocrinus respectively. Both are marked by ridges and 

 intervening fossae ; and that of Apiocrinus has the ridges 

 situated radially, as the fossae lodge the basals. But in Tetra- 

 crinus the ridges of the "article basal" (uppermost stem- 

 joint of Quenstedt) are interradial, just as they are in the " top 

 stem-joint " of Eiigeniacrinus, where, however, they are less 

 distinct. They thus correspond to those on the basal ring of 

 Apiocrinus, and not to those on the enlarged uppermost stem- 

 joint (article basal), which supports this basal ring. Why, 

 then, should they not be interpreted in the same way as the 

 interradial ridges of Apiocrinus, viz. as indicating the median 

 lines of the united basals ? May not the interbasal sutures 

 have disappeared in Tetracrinus as in the Norwegian variety 

 of JRhizocrinus y instead of remaining as in Apiocrinus? 



Quenstedt* says, however, " Auch diese Stucke (t. e. ober- 

 sten Saulenglieder) haben wie bei den anderen Eugeniacrini- 

 ten nur drei Blatterbriiche, konnen daher ebenfalls nicht als 

 Basalia bedeutet werden." But, as I have pointed out above, 

 we need not necessarily expect to find the same number of 

 cleavage-planes in the closely anchylosed basals as in the 

 united but still individually distinct radials ; and I do not 

 think that a mineralogical argument of this kind is of much 

 value in helping us over the morphological difficulties which 

 the supposed absence of basals involves. 



Plicatocrinus is another type which is generally said to 

 have no basals ; but specimens of it are rarely sufficiently well 

 preserved for a definite opinion to be formed upon this point. 

 According to Zittelf the basals are quite rudimentary and 

 rod-like, and concealed between the radials and the top stem- 

 joint. In this respect, therefore, Plicatocrinus would resemble 

 many of the Jurassic Comatulce and certain varietal forms of 

 Encrinus liliiformis. The same is probably the case in a few 

 species of the Pentacrinida3, which are commonly described as 

 being without basals. In one case at least, however, this is 



Baily's original description! of P. Fislieri 

 the first radials were called the basals ; and since the detec- 

 tion of this error it has been generally supposed that no 

 basals appear on the exterior of the calyx, as none are shown 

 in Baily's figure. I have recently, however, had the oppor- 

 tunity of examining for myself the few examples of this rare 



* Encriniden, p. 438. 



t Palseontoiogie, p. M87. 



| Ann. & Mag. !sat. Hist. ser. 3, vol. yi.pp. 25-38, pi. i. 



due to error. In 



