V. Botryocrinus. 407 



sac of B. cucurbitaceus, written by no less eminent an observer 

 than Prof. Sve*n Lovdn, has been published by Prof. H. 

 Trautschold in support of his view that the ventral sac of the 

 " Angulosi " is fissured for the exit of generative products*. 

 Whether Prof. LoA^en's words bear all the meaning that Prof. 

 Trautschold attributed to them I will not venture to say ; 

 neither can I say whether Prof. Loven himself meant all that 

 his words naturally imply, for when he was kind enough to 

 discuss the matter with me last year he had forgotten the 

 details of his observation. After describing the plates of the 

 sac as being prolonged laterally into " Beine," he says, " Die 

 von den Beinen der Platten umschlossenen Raume sind 

 vertieft," and " die Vertiefungen [sind] von Kalk frei." 

 Now I have very carefully examined not only the specimen 

 figured by Professors Angelin (Iconogr. pi. iv. fig. 9) and 

 Loven (loc. ci't.), but other even more instructive specimens 

 from Bursvik, Gotland, now in the Biksmuseum at Stock- 

 holm ; and I have not only been absolutely unable to demon- 

 strate spaces free from stereom — " von Kalk frei " — but when- 

 ever I have been able to clear away the matrix, a task which 

 though difficult is not impossible, I have invariably been able to 

 trace the, sutures between the plates across the synclinal folds, 

 in which position they have precisely the same appearance 

 as they have when traversing the anticlinal folds (fig. 2, p. 408). 

 I therefore affirm that there are neither slits, nor holes, nor 

 pores visible in the ventral sac of B. cueurbitaceus. I have 

 also examined with the utmost care all the specimens of B. 

 ramosissimus in the Stockholm Museum, and, while I have 

 been equally unable to demonstrate openings in any, I have 

 been able in one specimen, figured by Angelin, Iconogr. pl.xxiii. 

 f. 14, to trace the sutures across the depressions (fig. 3, p. 408). 

 In B. decadactyhis and B. pinnulatus the folds are much 

 narrower, and it is a very difficult matter either to clean them 

 or to see to the bottom of them ; but I have discovered 

 nothing that would lead one to suppose that the structure 

 differs in any essential point from that of the Swedish species. 

 I therefore conclude that slits, pores, and openings of every 

 description are absent from the ventral sac of Botryocrinus. 



As to the Anal opening itself, it seems to have been figured 

 by Angelin (Iconogr. pi. xv. ff. 9, 9 a) at the base of the sac 

 on its anterior side. Bui I do not quite understand the 

 figure ; the specimen is no longer to be found, and in no other 

 specimen have I been able to discover any trace of a similar 

 structure, in that, or indeed in any other position. 



* H. Trautschold, " Ueber Crinoideen, Zusatze und Bench tigiing-en,*' 

 Bull. Soc. Imp. Nat. Mosc. lvii. pp. 140-145, Moscow, 1882. 



28* 



