Lindstrom—On Zoantharia Rugosa. 411 



groove, by separating the operculum from a shell, "wMch. has been 

 fossilized with it adhering, and has therefore not been exposed to 

 weathering. It is then seen that the smaller septa are finely serrated. 

 The interior structure differs from that of G. Gotlandica in not being 

 vesicular. The chief mass of the solid shell consists of very close 

 and thin strata, which end downwards in a very acute apex. The 

 operculum is more regular and has a larger triangular area, and is 

 moreover 2:)rovided on both sides of the middle ridge with a series of 

 small tooth-like protuberances ("apophyses"), which are totally 

 wanting in C. Gotlandica, but are represented in GoniopJiyllum by 

 small irregular teeth on the cardinal area. There is consequently 

 no reason to unite C. sandalina with the other two species in one 

 genus, and I therefore propose that Calceola sandalina alone should 

 form the genus Calceola, that G. Gotlandica-he the type of a new genus ^ 

 Tmder the name BhizopJiylluvi, while Galceola Tennesseensis may per- 

 haps represent another genus A^ery closely allied to the last, but I 

 cannot decide this, as I have not examined any specimens of it. The 

 genus Calceola, as now limited, must, no doubt, be placed in the 

 family of the Gyatliopliyllince amongst the allied genera ; Goniophyllum 

 may be placed close to Ompliyma; BMzopJiyllum with its strongly 

 developed vesicular structure and indistinct septa, comes so near to 

 Gystiphyllum, that it may be considered as intermediate between the 

 GyatJiophyllince and Cystiphyllinee. The chief difference in the Cysti- 

 phyllince is that they have no distinct septal groove, and are wholly 

 vesicular. As to Calceola, the inner surface of its operculum would 

 give it a place near Goniopliyllum, but it is removed from that place 

 by its internal structure, which most closely resembles Chonophyllum, 

 which, as far as known, also consists of the same thin and funnel- 

 shaped strata. Calceola may then, at least, till further knowledge is 

 gained, be placed between Clionopliyllum and Goniopliyllum. The 

 series of the principal genera now mentioned would then be ; Cliono- 

 pliyllum, Calceola, Goniopliyllum, Ompliyma, Uliizopliyllmn, Cystipliyllum. 

 There is reason to believe that there are other families besides the 

 Cyatliopliyllince, in which some of the genera have been furnished 

 with an operculum. In the oldest strata of the Isle of G-otland 

 near Wisby, a fossil is occasionally found having, as it seems to me, 

 the nature of an operculum of one of the Zaplirentince. It is irregu- 

 larly triangular with rounded corners, generally very thin and almost 

 concave on the outside (Plate XIV, Figs. 22 and 23). The nucleus 

 is either central or lateral. On the interior sm^face is a triangular or 

 circular area (Plate XIV. Fig. 23), around which the margins form an 

 elevated border. This interior area is sinooth, sometimes wavy, and 

 crossed by from 8-9 filiform parallel and straight strite, which 



1 Rhizophyllmn, n. gen. ; Testa semiconica, appendicibus radiciformibus instructa, 

 structura interna cellulosa, calyx vesiculosus, in fundo fossa septali, septis perexiguis. 

 Operculuna nucleo centrali, area prajtenui, in superficie interior! dente medio valido, 

 fovea ovali superaddita, dentibus lateralibus nuUis. Species unica R. Gotlandicum, 

 F. Eoemer, in divisione suprema formationis Siluricae in Gotlaudia reperta. C'al- 

 ceolce, or ratber forms resembling Cakeolce, are by no means cbaracteristic of tbe 

 Devonian formation, as sucb also are found in tbe Lower Silurian strata of Western 

 Gotland in the mainland of Sweden. 



