FORAMINIFBRA OF THE ATLANTIC OCEAN 35 



chamber; aperture simple, at the base of the apertural face, or long 

 and slit-like, occasionally divided. 



Cretaceous (?) Tertiary and Recent. 



This genus as well as the whole family are characteristic of warm 

 shallow waters and generally coral-reef conditions. They often 

 occur in great numbers and show a great deal of variation. Double 

 and monstrous forms are not unusual. The student of this and allied 

 genera is referred to the work of Dreyer.^ In the Atlantic the genus 

 is most abundant in the general West Indian region. Little is known 

 of it from the eastern tropical Atlantic. 



Numerous writers have considered all the forms of Peneroplis as 

 varieties of a single species. Brady adopted this grouping in the 

 Challenger report, and many later authors have followed him. In 

 1915, Heron- Allen and Earland in their paper on the Recent Fora- 

 minifera of the Kerimba Archipelago, examined the early descrip- 

 tions and figures with the result that they used five distinct specific 

 names in their report. Some of these belong in other genera as now 

 recognized, and to them must be added certain species of d'Orbigny 

 based on material from the West Indies as well as one described by 

 Dr. J. M. Flint from material also of West Indian distribution. 

 For the stages of development in the microspheric and megalospheric 

 forms, the reader is referred to part 6 of Bulletin 71 of the United 

 States National Museum, where on pages 85 and 86, this develop- 

 ment is discussed. 



PENEROPLIS PERTUSUS (Forskal) 



Plate 12, figures 3-6 



Nautilus pertusus FobskIl, Descr. Anim., 1775, p. 125, No. 65. 



Peneroplis pertusus Jones, Parker, and H. B. Brady, Foram. Crag., 1865, 

 p. 19.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 204, 

 pi. 13, figs. 16, 17. — CusHMAN, Proc. U. S. National Mus., vol. 59, 1921, 

 p. 75, pi. 18, figs. 7, 8; Publ. 311, Carnegie Instit. Washington, 1922, 

 p. 78; Publ. 342, 1924, p. 71; Publ. 344, 1926, p. 83. 



Peneroplis elegans d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 

 1839, " Foraminifferes, " p. 61, pi. 7, figs. 1, 2. 



Test typically close coiled throughout, compressed, biumbilicate, 

 coils not usually completely involute, the earlier coils showing at the 

 umbilical region, periphery rounded to subacute; chambers numerous, 

 very variable in number, distinct, not inflated, low and broad; sutures 

 distinct, spiral suture depressed, other sutures often raised and 

 somewhat limbate; wall ornamented with fine striae parallel to the 

 periphery; aperture consisting of numerous pores along the middle 

 line of the apertural face. 



Size very variable. 



• Peneroplis, Eine Studie zur biologischenMorphologie und zur Speclesfrage (Leipzig, 1898, pp. i-vi, 1-U9 

 pis. 1-5 with figures 1-254, and text figs. A-Q). 



