SECOND, OB, SCHLOTHEIMIAN BRANCH. 135 



Sehlotheimia rotunda, Hyatt. 



Amm. lacunatus rotundus, Qoenst., Amm. Schwab. Jura, p. 167, pi. xxii. fig. 5, 6. 



This shell is more discoidal than any others described below. The whorls are 

 also stouter as a rule. The pilae on the umbilical shoulders are coarser and are 

 tuberculated according to Quenstedt's figures and descriptions. Amm. lacunoides, 

 Quenst,, 1 may be the young of this or an allied species. It occurs so far as 

 now known only in South Germany. 



Sehlotheimia lacunata, Hyatt. 



Amm. lacunatus, Buckman, Muroh. Geol. Cheltenh., 2d ed., p. 105, pi. ii. fig. 4, 5. 



Amm. lacunatus, Quenst., Amm. Schwab. Jura, p. 167, pi. xxii. fig. 1-4. 



Amm. lacunatus, Ddm, Etud. Pal. d. Bas. d. Rhone, p. 120, pi. xxi. fig. 18-20. 



Amm. lacunatus, Weight, Lias Amm., p. 330, pi. lvi. fig. 16-18. 



Amm. deletum, Canavari, Lias v. Spezia, Paleontogr., XXIX. pi. xviii. fig. 13. 



Amm. sp. ind. cfr. lacunata, Canavari, Fauna del Lias, Mem. del. Carta Geol. d' Italia, III., 18S8. 



Localities. — St. Thibault, Semur. 



The pilae are not coarse or tuberculated at the umbilical shoulders. The 

 whorl is also more compressed and the involution greater than in Schlot. rotunda, 

 covering about two thirds of the side. The young according to the figures given 

 are also not smooth to so late a stage as in that species. The description of the 

 originals in the Geology of Cheltenham in a measure makes up for the figures. 

 The latter belong to a discoidal species, the former gives the usual combination 

 of an involute shell, narrow abdomen, flattened sides, and half-concealed whorls. 

 An important statement is also added, that the " ribs " cross the abdomen in the 

 young. The latter indicates the possibility of a direct derivation of the second 

 subseries from Schlot. catenata, and also serves to confirm the identification of 

 Wright's species with this, since Wright mentions the same characteristics. 



Sehlotheimia Geyeri, Hyatt. 



Schlot. lacunatus, Geyer, Liasis. Cephal. v. Hierlatz b. Hallstadt, p. 259, pi. iii. fig. 22, 23. 



This species has fine but sparsely distributed pilge at the umbilical shoulders 

 which speedily divide into two or more finer pilae. The abruptness of the divis- 

 ion gives the umbilical pilse a resemblance to those of Schlot. Quensteclti in Geyer's 

 figures, but there are no tubercles, and the involution covers about four fifths of 

 the side, and the whorls are considerably compressed. 



Sehlotheimia angustisulcata, Geyer. 



Schlot. angustisulcata, Geyer, Liasis. Ceph. Hierlatz b. Hallstadt, p. 256, pi. iii. fig. 24, 25. 



The pilas are finer, the whorls more compressed, the involution quite as exten- 

 sive as in the preceding. The sutures which are figured in this species, if they 

 can be correctly given in so small a figure, are quite distinct from those of the 

 similar involute forms of Sehlotheimia. 



1 Amm. Schwab., p. 162, pi. xxi. fig. 24, 25. 



