BUB-CLASS II 



HYDROZOA ACALEPHAE 



121 



FIG. 210 



Eichstiidt, Bavaria, 

 in^outliiie.) 



1/7 natural size. (M 



.itho-rnphic slat'-s : 

 issing parts restored 



1'nder exreptioiiallv ta\ ..arable conditions, however, ;is in tin- Lithographic 

 Slat.-s (I'pprr Jurassic) ,,f Kirlistadt and Sul.-nbofen, impressions ..f these deli- 

 cate organisms are sometimes pre- 

 served, which admit of accurate 



iatic determination, 



The best preserved and at 

 tin- same time the most abundant 



speriesis/i'///'7"/////rx ii>!i,,ii-<i/i<!it.<, /; : -: ; -' 

 Hacckcl, bclongini^o tilt- Arras- /:;V. r 



pcdotc t'.-m lily of Rhizoetomidae. 

 Impressions also occur in flinty 

 concretions of the Upper Cre- 

 tacruus, which arc most nearly 

 referable to tin- Medusae. Of a 

 more <|iiestionalle nature are the 

 organisms occurring in the Cam- 

 brian sandstone of Lugmies, 

 Sweden, and described liy Torrell 

 under the name of Spofangopsis, 

 luit which Xathorst assigns to the 

 Acalephs. In the same strata 

 also are found those peculiar 

 t'ucoidal structures known as 

 Knjiliifttm-j which are generally 

 supposed to be of A-egetable 

 oii^in. Xathorst has brought forward evidence, however, to show that these 

 may really have been produced by the trails of Jelly-fishes. Here also should 

 be noticed the forms described by Nathorst as Medusites, from the Lower 

 Cambrian of Sweden, which this author regards as casts of the gastric cavity of 

 Jelly-fishes. According to Walcott, similar fossils are common in Alabama. 1 



'/'.. .M.-nioir on the Anatomy and Affinities of the Medusae (Phil. Trans.), 1849. Kn>',\ 

 /.'.. !Yl,.-r rinr Mrdnsr in F.-u-r>trm BttznngBber. Wi.-n. Akad. Bd. LILfc 1865. Haeckel, E., Ueber 

 foodie M.-duscii (Z.-itselir. fiir wisst-iiM-haft. Zodl. lid. XV. and XIX.), 1865 and 1870. Neues Juhrk 

 fur MiniTiilngie, 1866. Jenaisclir Zi-its<-hr. Bd. VIII., 1874. System der Meduseu, Bd. I. and II., 

 .Ii-na, 1880-81. Nathorst, A. G., Om Aftryck af Medusor, etc. (K. Svenska Vetensk. Akad. Handl., 

 IM. XIX.), 1881. A,,,,,,,,,,. L. /-., Ueher jurassische Meduseu (Abhandl. k. baier. Akad. Bd. XVII.), 

 1883. A'/-"//'//. -I.. Uebet f..ssilc Medusen (Mem. Acad. Imp. St. Petersb. vol. XVL, 7th Ser.), 1871. 



/'"lifi'l, //.. AltiH-nuivlie .Medusen (Festschrift zum 70ten Geburtstage R. Leuckarts), 1892. 

 //>//, ./., Palaeontology of N.Y., vol. I.. 1847, and III., 1859. 20th Report N.Y. State Cabinet 

 X.-it. Hi>t., l.xti.S. /,^>*/v>r<A, C., Notes on British Graptolites (Geol. Mag. X.), 1873. Hopkinson, J., 

 ini.l Liijiinn-ih. c., (Jraptolites of tli- Arenig and Llandeilo rocks of St. David's (Quar. Journ. Geol. 

 CXI. . 1875. Linnarsfton, (/., and ^V/W/o/sv,,,, //. A., On the vertical range of Graptolites in 

 Sw.-dn; . III.), 1876,Lapworth, C., On Scottish Monograptidae (Geol. Mag. III.), 1876. 



On thr (Jraptolit.-s ,f County Down (Ann. Rep. Belfast Nat. Field Club, I., Part IV.), 1877. 

 //" //, A'.. I Mr Fauna lrs Graptolitlien-Gesteins (Neues Lausitzsches Mag. LI V.), 1878. Kayser, E., 

 In Alihandl. gi-ol. Spocialkarte von Preussen II., Heft 4, 1878. Linnarsson, G., Om Gotland's 

 <:rapt.lit.-r Svms. Vet. -Akad. Forh. XXXVI.), 1879,Lapworth, C., Distribution of the Rhabdo- 

 plioia Ann. Majr. Xat. Hist. III.-VI.), 1879-80. On new British Graptolites (op. cit. V.), 1880. 

 TiiWn-fii, N. J.. i Mi spn-i.-s of I )id viuograptus (Geol. For. Stockholm Forh. V.), ISSO.Toruquisf, 

 X /... Studi.-r r.fv-r lU-tiolitcs (Geol. For. Stockholm Forh. V.), 1881. Also papers by Tb'rnquist 

 and Liiinarssnn in sanir volume, pp. 292-326. Holm, G., Skandinavien's Graptoliter (Sveus. Vet.- 

 Akad. Forh. XXXVIII.), ISSl.TuUberg, S. A., Skane's Graptoliter (Sven. Geol. Underslikn., Ser. 

 <'-. I. and II.\ lSS2-S3.8frencer, J. W., Graptolitidae of the Upper Silurian System (Bull. Univ. 

 Mo. I., and Trans. St. Louis A. ad. Sci. IV.), 1884. Jaekel, 0., Ueber das Alter des Graptolitheu- 

 J.-sti-ins iZ.-itsrlir. dentsch. geol. Gesellsch. XLI.), 1890,Barrois, C., Memoire sur la distribution 

 dcs Graptolites en France (Annal. geol. soc. Nord), 1892. 



