KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:G 2. 105 



parvus, Hall (Homocrinus), Nat. Hist. N. Y. Palaeont., vol. II, p. 185; 1852. Of this 

 Wachsmuth and Springer say (Revision I, 78) »Probably a very young individual 

 of some other species». It is however doubtful to what genus this belongs; there 

 is nothinor to show that it is a Homocrinus as now nnderstood. Mr. S. A. 

 Miller retains it as the type of Homocrinus, but has proposed no new name 

 for H. cylindricus and H. scoparius. It seems safer to regard it as insufficiently 

 deseribed. 



polydactylus, Shumard {Homocrinus), Träns. Aead. Sci. St. Louis, vol. T, p. 78; 1867. 

 This was referred to Dendrocrinus by Wachsmuth and Springer (Revision, I, 77). 



poh/xo, Hall (Cyathocrinus), Träns. Albany Inst., vol. IV, p. 199; 1863. This was referred 

 to Homocrinus by Wachsmuth and Springer (Revision, III, 220) but it is almost 

 eertainly a Botryocrinus. 



proboscidialis, Hall (Homocrinus), Nat. Hist. N. Y. Palacont., vol. TIT, p. 138; 1861. 

 There would have been no reason to doubt that this was a Homocrinus, had not 

 Hall remarked that it differed from H. scoparius in the arrangemcnt of the 

 plates of the bodv. 



scoparius, Hall (Homocrinus), Nat, Hist. N. Y. Palaeont., vol. III, p. 102; 1861. This is 

 the best preserved species of the genus. 

 The following then are the only species that can be legitimately referred to Homo- 

 crinus. — H. ancilla, Hall sp., H. cylindricus, Hall, H. nanus, C. F. Römer sp.?, H. 



proboscidialis, Hall? and H. scoparius, Hall. To these is now added one new species 



from Gotland. 



Homocrinus tenuis, n. sp. 



(Plate IV, fitfs. 143—147). 

 Diagnosis. 



Dorsal cup almost regularly conical, slightly higher than wide. II? Ii and BB higher 

 than wide. RR nearly as high as BB, very slightly wider than high, project slightly from 

 the cup. Arms dichotomise regularly at intervals of 4, 5 or 6 ossicles; reäch about 47 2 

 times length of cup. Anal tube reaches more than half the length of the arms and widens 

 above. Stem subpentagonal proximally, of regularly alternating ossicles. 



A small slab of sandstone in the Riksmuseum, interlaced with stems of crinoids, 

 contains amongst other genera, such as Taxocrinus, 7 or more specimens of this delicate 

 little species, the total effect being very like that of the slabs of Lower Helderberg sand- 

 stone that have been found covered with Homocrinus scoparius. From these seven speci- 

 mens four well-preserved may be specially selected for description, and lettered a, b, c, d. 



Description. 



The Dorsal cup is almost regularly conical, not contracting above, but with the 

 radials slightly projecting as in Botryocrinus. The shapes of the plates agree exactly with 

 the generic diagnosis. The following are the measurements noted: 



K. Sv. Vet. Akad. Handl. Band 25. N:o 2, 14 



