118 



or Brazil. Cushman & Bronnimann (19486) distinguished two 

 species of Ammotium with strong lateral compression, 

 namely A. directum and A. diversum. To these has to be 

 added a third, A. subdirectum Warren, 1956. 



Ammotium directum, the more common species, as 

 described above, has strongly incurved sutures of an asym- 

 metrical type with a shorter outer or marginal branch and a 

 longer, inner branch, which slants toward the initial spire (see 

 Fig. 47). Occasionally, some sort of chevron pattern is 

 formed but rarely to the extremes indicated by Milieu's 

 drawing (pi. 5, fig. 4a; our Fig. 1.4a). A. directum is always 

 characterized by this asymmetrical type of suture. The test, 

 moreover, is strongly compressed laterally and the width of 

 the flattened chambers does not increase much in the course 

 of growth. The aperture is slit-like and situated at the apex of 

 the final chamber, more or less in a marginal position. The 

 initial spiral consists of several chambers. 



A. diversum is less common than A. directum. The only 

 significant difference lies in the sutural shape, which in the 

 former in the final ontogenetic stage, is always more or less 

 horizontal, slightly incurved and in extremes, no longer 

 asymmetrical (see Cushman & Bronnimann, 19486, pi. 7, figs 

 5,6). Furthermore, in this species, the sutures of the early 

 uniserial portion are slanting inward toward the initial coil. 

 Occasionally, there is a suggestion that the two are linked by 

 transitional forms. Should the two be ultimately considered 

 synonymous then we would prefer to retain A. directum, as 

 this, although printed on the same page, was described first. 

 For the time being, however, both are retained. 



A. subdirectum was described by Warren (1957, pi. 4, figs 

 6-8) from the marshes of the Buras-Scofield bayou region of 

 southeastern Louisiana. We have encountered it but rarely in 

 the mangrove sediments of Acupe, Brazil and Warren him- 

 self (1957: 33) mentioned that . . . 'specimens were rare 

 wherever found except in one of the polyhaline marsh 

 samples'. Two specimens from Acupe (BMNH nos ZF 5000 

 and 5001) are illustrated in Figs 48,49,51,52 for comparison 

 with the Malay species of Ammotium. A. subdirectum is a 

 many-chambered species characterized by the same asym- 

 metrical type of sutures as found in A. directum. In the final 

 growth stages the sutures may become more or less symmetri- 

 cal and arranged in a chevron-like pattern, as shown in 

 Millett's drawing of the fragment illustrated in pi. 5, figs 7a, b; 

 Fig. 1.7a,b. Figs 36,45,46 could represent this specimen 

 which is part of either an A. subdirectum, or an A. directum 

 as discussed above. Normally, A. subdirectum is about twice 

 as long as A. directum and composed of more chambers. The 

 test is slightly incurved and the width of the chambers, seen 

 laterally, increases quite strongly towards the final chamber. 

 The aperture is a narrow oblong slit, as in A. directum and A. 

 diversum, and situated at the apex of the final chamber, more 

 of less in a marginal position (see Figs 48,49,51,52). In all 

 three species, the agglutinant is fine-grained and the surface 

 of the test usually appears smooth, occasionally even some- 

 what glossy. 



Dimensions of figured specimens (BMNH no. 

 1955.11.1.1118). Height of test — 290 ^m; maximum width of 

 final chamber — 73 \am. 



(BMNH no. 1955.11.1.1119). Height of fragment — 

 270 \im; length of apertural slit — 45 \un. 



(BMNH no. 1955.11.1.1120). Height of test — 330 \im. 



Environment. This species was found only at Station 9 



P. BRONNIMANN AND J.E. WHITTAKER 

 (Area 1). It is a typical brackish-water species. 



Genus ARENOPARRELLA Andersen, 1951a 



Type SPECIES. Trochammina inflata (Montagu) var. mexi- 

 cana Kornfeld, 1931. 



Arenoparrella mexicana (Kornfeld, 1931) 



Figs 1.3,9-12 



1899 Haplophragmium agglutinans d'Orbigny var. triper- 

 forata Millett: 358 (pars); pi. 5, figs 3a, b only; non 

 figs 2a, b. 



1931 Trochammina inflata (Montagu) var. mexicana Korn- 

 feld: 86; pi. 13, figs 5a-c. 



1951a Arenoparrella mexicana (Kornfeld); Andersen: 31; 

 fig. la-c. 



19516 Arenoparrella mexicana (Kornfeld); Andersen; 96; 

 pi. 11, figs 4a-c. 



1977 Arenoparrella mexicana (Kornfeld); Zaninetti et al.; 

 pi. 2, figs 3,7. 



Remarks. One of Millett's illustrated specimens (1899, pi. 5, 

 figs 3a, b; reproduced here as Figs 1.3a,b) of H. agglutinans 

 var. triperforata is, in fact, a typical specimen of Arenopar- 

 rella mexicana (Kornfeld). It is re figured here by SEM (Figs 

 9-12) and shows that the original drawing of the edge view in 

 particular, is very misleading. As discussed above under the 

 description of the lectotype of Acupeina triperforata (Millett), 

 the edge view of fig. 3b also suggests that there are only three 

 large everted apertures. The reality is an aperture consisting 

 of a vertical slit lined by slightly uplifted borders, in an 

 interiomarginal position, of about 50 ^m length and 8 \im 

 width, and 12 small, irregularly arranged, rounded pores 

 above this primary aperture, of between 5 and 10 urn diam- 

 eter, devoid of everted rims. Millett's specimen (BMNH no. 

 1955.1.1.1075) is tilted so far forward in apertural view that 

 the primary vertical slit, so clearly visible in fig. 3a, might not 

 have been seen, but it is puzzling to understand why he 

 illustrated the apertural pores as he did. Millett's material 

 from stations 5 and 9 quite clearly represents both Acupeina 

 triperforata and Arenoparrella mexicana, which is not surpris- 

 ing as they commonly occur together. The illustrated speci- 

 men of the latter is completely involute (hence the small axial 

 depression is closed). The final whorl consists of 4, axially 

 compressed chambers which gradually increase in size with 

 growth. In edge view the periphery is rounded. Umbilical and 

 spiral sutures are poorly defined and the agglutination is 

 rather fine-grained and produces a smooth surface. 



Dimensions of figured specimen (BMNH no. 

 1955.11.1.1075). Maximum diameter — 290 fim; minimum 

 diameter — 240 |xm; axial height (thickness) — 120 \im. 



Environment. See under Acupeina triperforata (p. ). 

 Arenoparella mexicana is a typical tropical and subtropical 

 mangrove swamp species. 



Genus HAPLOPHRAGMOIDES Cushman, 1910 



Type SPECIES. Nonionina canariensis d'Orbigny, 1839. 



Remarks. The wall structure of the type species is unknown; 

 we are not even sure of the apertural position, for that 

 matter. Although the wall of H. wilberti, the species in the 



