116 



P.BRONNIMANN AND J.E. WHITTAKER 



Ammotium pseudocassis (Cushman & Bronnimann, 

 1948) Figs 1.5, 50, 53 



1899 Haplophragmium cassis (Parker); Millett: 359 (pars); 

 pi. 5, figs 5a, b only (non Lituola cassis Parker, 1870). 



19486 Ammobaculites pseudocassis Cushman & Bronni- 

 mann: 39, 40; pi. 7, figs 12a,b. 



1983 Ammoscalaria pseudospiralis (Williamson); Haman: 

 72; pi. 5, fig. 5 (non Proteonina pseudospiralis Will- 

 iamson, 1858). 



Remarks. This species was illustrated by Millett (1899, pi. 5, 

 figs 5a, b; here reproduced as Fig. 1.5a,b) under the name of 

 Haplophragmium cassis (Parker). It is an upper fragment of 

 an elongate test consisting of three rounded (in transverse 

 section), hardly compressed chambers. Millett's drawing 

 shows the inward and backward trending sutures and the 

 rounded aperture in marginal position. Within the concept of 

 this species, Millett also included specimens of Ammotium 

 directum (Cushman & Bronnimann)(Figs 1.4a,b, 31,?36) and 

 Ammoastuta salsa Cushman & Bronnimann (Figs 1.6a,b, 35). 

 As already mentioned, the fragment of A. pseudocassis 

 illustrated by Millett in his pi. 5, figs 5a, b (see our Figs 

 1.5a,b) could not be found in his Malay collection. 



For comparison, we have illustrated typical specimens in 

 lateral view of A. pseudocassis from the mangrove sediments 

 of Guaratiba, Brazil (see Zaninetti et al. , 1977), one by SEM 

 (Fig. 50), the other by optical photography in immersion 

 (Fig. 53). In the latter specimen the early spiral is reduced to 

 two chambers, a relatively large proloculus of 50 (xm diam- 

 eter, and a larger deuteroloculus of about 75 urn diameter. 

 The embryonic chambers are not enclosed by other spiral 

 chambers, as in A. pseudospirale (Williamson, 1858). The 

 total number of chambers, including embryonics, is eight. 



Ammotium pseudocassis differs from A. pseudospirale by 

 the elongate, somewhat incurved test, the less compressed 

 and elongate chambers and the reduced initial spire. The final 

 chamber is usually the dominant one, making up about 

 one-third of the test. It narrows toward the oblong aperture 

 and extends on the inner side of the test toward the initial 

 spiral. The early coil, represented by a reduced spire, consists 

 of very few chambers only. A typical embryo consists of two 

 very thin-walled chambers, a large proloculus, about 

 40-60 um in diameter, and an equally large deuteroloculus. 

 The embryo may form all the initial portion of the test. We 

 have never found a microspheric specimen of A. pseudocassis 

 and where the taxon is frequent, A. pseudospirale is usually 

 absent. The aperture of the holotype of A. pseudocassis, 

 deposited in the U.S. National Museum of Natural History 

 (registration no. 56764), is not as circular as that shown in 

 Millett's drawing, but distinctly oblong. As in Ammotium 

 cassis and A. morenoi, the aperture is situated at the apex of 

 the last chamber in a marginal position (see Cushman & 



Bronnimann, 19486, pi. 7, fig. 12b). However, it seems that, 

 when the final chamber is hardly compressed, the aperture 

 may become rather centred and more rounded than slit-like, 

 but never completely circular. 



Dimensions. Fig. 50: Height of test — 480 \im; maximum 

 width — 150 um; height of final chamber — 290 pm; maxi- 

 mum diameter of aperture — 50 um. 



Fig. 52: Height of test — 575 pm; maximum width — 170 

 um; height of final chamber — 375 mm; maximum diameter 

 of aperture — 75 um; thickness of wall (final chamber) 

 10 um. 



Environment. The group of forms referred by Millett to H. 

 cassis (Parker) occur only at Station 9, Area 1, . . . 'where 

 they are not uncommon'. They are all exclusively brackish 

 water species. 



Ammotium directum (Cushman & Bronnimann, 1948b) 



Figs 1.4,(?1.7),31,36,37,45-47 



1899 Haplophragmium cassis (Parker): 359 (pars); pi. 5, 

 figs 4,?7 only (non Lituola cassis Parker, 1870). 



19486 Ammobaculites directus Cushman & Bronnimann: 

 38; pi. 7, figs 3,4. 



1956 Ammotium sp. D. Warren: 139; pi. 1, figs 19-21. 



1957 Ammobaculites directus Cushman & Bronnimann; 

 Todd & Bronnimann: 23; pi. 2, fig. 6 only (non Fig. 

 7). 



1988 Ammotium casamancensis (sic) Debenay: 46,47; pi. 

 1, figs 1-3. 



Remarks. Under the name of H. cassis (Parker), Millett 

 (1899, pi. 5, figs 4a, b; here reproduced as Figs 1.4a,b) 

 illustrated a specimen of Ammotium directum (Cushman & 

 Bronnimann). Our identification is based on the overall 

 outline, the shape of the sutures, and the strong lateral 

 compression of the test. The specimen illustrated by SEM in 

 Fig. 31 is that very same specimen, viewed from the other 

 side. 



The fragment shown in Millett's fig. 7, which he compared 

 to ... 'a species of Reophax, with the plan of growth and 

 chevron-shaped chambers of Frondicularia may be that 

 illustrated by SEM in Figs 36,45,46, although the chevron- 

 shaped chambers are exaggerated, as they are in the drawing 

 of fig. 4a (compare with our Fig. 31). The aperture in both 

 specimens is slit-like, without an everted border, and is 

 situated at the apex of the final chamber. For comparative 

 purposes, a lateral view of a specimen of A. directum, from 

 the mangrove sediments of Acupe, Brazil (BMNH no. ZF 

 4999) is illustrated in Fig. 47; the asymmetrical sutures are 

 well exhibited. 



The tests of Ammotium directum in the Millett Collection 

 are extremely fragile, in contrast to those found in Trinidad 



Figs 28-30 Trematophragmoides bruneiensis Bronnimann & Keij. Side, edge and view of other side (X115). BMNH no. 1955.11.1.1136. 

 Figs 31, 36, 37 Ammotium directum (Cushman & Bronnimann). Side views of three separate specimens (X 185, 205 and 185, respectively). 



BMNHnos. 1955.11.1.1118-1120. 

 Figs 32-34 Ammotium morenoi (Acosta). Side, edge and oblique apertural views (X250). BMNH no. 1955.11.1.1122. 

 Fig. 35 Ammoastuta salsa Cushman & Bronnimann. Side view (X 200). BMNH no. 1955.11.1.1121. 

 Figs 38-41 Ammotium cassis (Parker). Apertural, oblique apertural, side and edge views (X45). Lectotype, BMNH no. ZF 4637, Gaspe 



Bay, Gulf of St. Lawrence, Canada. 

 Figs 42-44 'Ammobaculites' exiguus Cushman & Bronnimann. Fig. 42, Side view (X185). BMNH no. 1955.11.1.1058; Figs 43,44, 



Oblique-apertural and edge views (X175). BMNH no. 1955.11.1.1057. 

 All from Millett Collection, Malay Archipelago, except where stated. 



