PENEROPLIS CYLINDRACEUS. j 33. 



1. Peneroplis planatos (Fichtel and Moll). Plate VI, fig. 5. 

 Part I, 1866, page 19. 



Characters. — Of the broad, complanate forms of Peneroplis, only one specimen 

 has been met with in the Crag. It is an outspread variety of P. pertusus. This 

 individual shows irregularly periodical restrictions in its growth, owing to 

 unfavorable circumstances in its surroundings ; but otherwise it is a good 

 representative of PL pla.natus. See Brady, Report ' Challenger,' pages 204 and 

 206, pi. xiii, fig. 15 ; fig. 5, pi. vi, is equivalent to Carpenter's fig. 1, pi. ii, ' Philos. 

 Trans.,' vol. cxlix, 1859. 



Occurrence. — See page 134. 



2. Peneroplis (Dendritina) arbuscula (d'Orbigny). Plate III, figs. 48, 49. 

 Part I, 1866, pages 17 and 19 ; and Appendix II, Table, No. 17. 



Characters. — This is one of the medium-sized nautiloid forms of Peneroplis 

 pertusus (Forskal), having a dendroid or ramifying orifice. See Brady, Report 

 ' Challenger,' 1884, p. 204. PI. Ill, figs. 48, 49, are equivalent to Carpenter's 

 figs. 12 and 16, pi. ii, ' Philos. Trans.,' vol. cxlix, 1859 ; and, for the aperture, 

 to the woodcuts of Dendritina, figs, a and c at p. 9, and figs. a. — d at p. 11 of the 

 same memoir. 



Occurrence. — See page 134. 



3. Peneroplis cylindkaceus {Lamarck). Plate VII, fig. 3. 



Part I, 1866 (Spire-Una), pages 18 and 19 ; and Appendix II, Table, No. 18. 



Characters. — This modification of Peneroplis has been known as Spirolina 

 cylindracea, and was so described in Part I of this Monograph. Synonyms and some 

 figures are given by Brady, Report ' Challenger,' 1884, p. 205, pi. xiii, figs. 20, 21. 



The figure of P. cylindraceus, PI. VII, fig. 3 (lost specimen from the Crag), 1 is 

 from a sketch by the late Dr. H. B. Brady. 



1 See Part I, page 11, foot-note. 



