LARVII'ORM CRINOIDS V 



were obtained from a single locality whereas "immature" forms were col- 

 lected at a number of other places, and it is highly improbable that if these 

 were really immature specimens they should occur at most places without 

 "adult" specimens associated with them; 2 (2) the "immature" forms are 

 too diverse in character to all belong to the same species ; (3) the plates which 

 compose the calyxes of the "immature" specimens are joined together so 

 solidly that they were not separated upon the death and decomposition of 

 the animals that formed them, but in the larval forms of modern crinoids 

 the plates are thin, porous, and not solidly joined together; (4) the specimens 

 in our collection, which strongly resemble some of. Carpenter and Etheridge's 

 "immature" forms, are mature as is shown by the fact that numerous speci- 

 mens of a single species are nearly all of uniform size and in the same stage 

 of development — if they were immature it is highly improbable that all of 

 the specimens should have died at the same stage in their development ; 

 (5) according to the interpretation of Carpenter and Etheridge the relative 

 size of the oral vault must have decreased with the growth of the crinoid 

 and at the same time the number of arms must have increased. Wanner's 

 study of a large number of specimens from Timor has shown that neither 

 of these suppositions is true but that the relative size of the oral dome and 

 the number of arms are constant characters among the various sized speci- 

 mens belonging to a single species [17, p. 10]. 



It is concluded, therefore, that the "immature" specimens are not con- 

 specific with the "adult" forms, and in this view Wanner agrees [17, pp. 

 10-11]. It remains to decide whether or not it is justifiable to retain them 

 in the same genus. 



Crinoids that have been described as Allagccrinus are few in number. 

 From America there are A. carpenteri Wachsmuth [11, p. 40] which has 

 recently been removed to the genus Catillocrinus by Springer, [10, p. 28] 

 and A. amcricamts Rowley [7, p. 219] which is considered below in more 

 detail. Foreign species are: A. multibrachiatus, and A. uralcnsis Jakovlev 

 [5, pp. 184-185], and the variety of the latter nodocariiiatits, which should 

 probably be considered a distinct species, from the Ural Mountains ; and 

 A. indoaustralicus, A. jakovlevi, A. in flatus, A. acntus, A. procerus, A. 

 quiuquclobiis, A. cxcavatns, A. quinquebrachiatus and A. oruatits Wanner 

 from Timor [17, pp. 15-27]. 



The foreign species described by Wanner and Jakovlev are apparently 

 similar in most of their characters to those in our collections upon which 

 the observations in the following discussion are based. 



The crinoids under discussion resemble A. austinii (as restricted to the 

 "adult" specimens of Carpenter and Etheridge) in two respects: (1) the 



2 Professor Wanner states that J. Wright has collected more than 300 "immature" 

 specimens from bed No. 1 at Invertiel. Fife, and with them he found onlv one or two of 

 the "adult" forms. [17, p. 11, footnote.] 



