228 Annals of the South African Museum. 



two forms are closely comparable, though the adult portloclci 

 develops ventral tuberculation. 



P. epiplectns, Redteubacher,* included by Clrossouvre and Nowak 

 in the synonymy of P. colligatus, differs both from the latter and from 

 the present example in the pronounced peripheral sinus in the costation. 



P. quiriqitinae (Philippi), Steiumann sp.f resembles the Zululaud 

 example in suture-line, and has a similar straight principal lobe, but 

 is too thin and too closely costate. 



" A. newberryamis," Meek sp., as figured by G-abb has a 

 similar suture-line, but the costatiou is finer and closer, and the 

 whorl-section is more compressed than in the specimen under 

 description. On the other hand, Whiteaves figures as A. new- 

 berryanus, Meek, an Ammonite which, judging by comparable 

 examples from Vancouver Island in the British Museum, || belongs 

 to a group of forms quite different from the Parapachy discus here 

 discussed and related to the isculensis-gToup of Nowak and to Kossmati- 

 ceras. Of Japanese forms, P. teshionensis, Jimbo,^ is less globose and 

 less involute than the African example ; it also has umbilical tubercles 

 and a less complex suture-line. P. naumanni, Yokoyama,** resembles 

 the specimen here described in globosity, but has varices with close 

 costation, and a comparatively large umbilicus. 



* "Ceph. Fauna d. Gosau-Sch.," ' Abh. K.K.E.A.,' vol. v (1873), p. 121, 

 pi. xxviii, fig. l. 



t " Beitr. z. Geol. and Pal. S. Amer.," Ill, " D. Alt. und d. Fauna d. Quiriquina 

 Sch. in Chile," N. Jb. f. Min., etc., Beil. Bd. x (1895), p. 74, pi. vi, fig. 3, Text- 

 fig. 5 on p. 77. 



t 'Pal. of Calif./ vol. i (1864), p. 61, pi. xxvii, fig. 199, and pi. xxviii, 

 fig. 199 . Whiteaves (' Mesoz. Foss.,' p. 107), included this form in A. 

 complexus var. suciensis, Meek ; later (ibid., p. 344) renamed Pachydiscus 

 suciensis, Meek sp. (The reference is [wrongly] to A. brewerianus, Gabb, in 

 both cases.) Three examples, doubtfully referred to Pachydiscus complexus, 

 var. suciensis, by Kossmat, from Vancouver Island in the British Museum 

 Collection, are quite different from the Californian Ammonite, which also is 

 quite different from Meek's original A. complexus ?, var. suciensis ('U.S. Geol. 

 and Geogr. Surv.,' Bull. No. II, 1870, p. 369, pi. v, fig. 2). 



' Mesoz. Foss.,' I, pt. ii. " Foss. Cret. Eocks Vancouver, etc.," ' Geol. Surv. 

 Can.,' 1879, p. 109, pi. xiv, figs. 1 and 1 a. 



|| Associated with P. otacodensis, Stoliczka (Whiteaves, loc. cit., I, V, 1903, p. 

 340, pi. xlvi, fig. 1, and 'Trans. Eoy. Soc. Can.,' 2nd ser., vol. i, sect, iv, 1895 

 [1896], p. 131), and other species of Parapachydiscus labelled by Kossmat (see 

 ' Jb. K.K. Geol. E.A.,' vol. xliv [1894], p. 472). 



*|[ " Beitr. z. Kenntn. d. Fauna d. Kreidef. v. Hokkaido," ' Palseontol. Abh. 

 Dames & Kayser,' vol. vi, pt. iii (1894), p. 30 (176), pi. iii, fig. 1. 



** " Verstein. a. d. Japan Kreide," ' Palseontograph.,' vol. xxxvi (1890), p. 187, 

 pi. xxii, fig. 1. 



