556 MESSES. E. IIEEON--ALLEN AND A. EABLAjSD OS THE 



(T. 1882, FEP. p. 159, pi. xvi. (xxiv.) fig. 24). At Stns. 1 and 2 abnormal specimens 

 were found in which the axis of growth changed radically at an intermediate stage, 

 proceeding at a right angle to the original plane. 



21. Spiroloculina planissima (Lamarck). (PL XLI. figs. 1-5.) 



Miliolites planulata, ys,v. planissima Lamarck, 1816, etc., ASV. 18.22, p. 613. no. 4 c. 



,, Parker, Jones, & Brady, 1859, etc., NF. 1860, p. 470, no. 25. 

 Spiroloculina planulata Jones, Parker, & Brady, 1866, etc., MFC. 1895, pp. 103, 104. 



„ compressiiiscula Karrer, 1867, FO. p. 28, pi. ii. fig. 4. 



„ tenuirostru Karrer, ibid. fig. 5. 



„ planissima Wiesiier, 1912, AM. p. 209. 



9 Stations. 



Lamarck divides his species Miliolites planulata into three forms [a, b, and c) — the 

 first («) being typical S. planulata, the second {h) apparently ^S". nitida, the third (c) 

 var. planissima described as " margine carinata." This description, short as it is, 

 seems quite sufficient to identify the form with a type which is abundant in many of 

 the Kerimba dredgings, and which we now figure, 'i'he shell is of a normal planulata 

 type, with, in the young specimens, a sharp marginal keel to both of the peripheral 

 chambers. With an increase in size the final chamber tends to become bicarinate, 

 thus passing into the normal ;iS'. planulata. This bicariuation of the final chamber is 

 easily traced in our specimens by a number of examples, of which we figure one in 

 w^hich the second carina extends over only half the length of the shell. This second 

 carina begins sometimes at the oral and sometimes at the aboral end of the shell. 

 The texture is porcellanous, but seldom highly polished. The form may in its extreme 

 tenuity be compared with the 8. compressiiiscula of Karrer {ut supra), which, however, 

 differs in having a rounded edge to the peripheral chambers, and with the same 

 author's S. tenuirostra [ut supra), which has a sharp edge but involute chambers, and 

 is thicker at the middle of the shell than at the periphery. The S. papyracea of 

 Burrows, Sherborn, and Bailey (B. S. & B. 1890, EC. p. 551, pi. viii. fig. 1) is a 

 similarly compressed form and apparently identical with Karrer's 8. compressiuscula. 



The type is not very generally distributed, but occurs in considerable numbers at 

 some Stns., especially at Stns. 3 & 9. 



Specimens average 1-0-1 '7 mm. in length, -o-l'O mm. in breadth, and T-'2 mm. in 

 thickness. 



22. Spiroloculina tenuis (Czjzek). 



Quinqueloculina tenuis Czjzek, 1848, FWB. p. 149, pi. xiii. figs. 31-34. 



„ Reuss, 1849-50, FOT. p. 885, pi. v. (1.) fig. 8. 

 Spiroloculina tenuis Brady, 1884, FC. p. 152, pi. x. figs. 7-11 (References). 

 Miliolina tenuis Brady, 1887, SBllP. p. 882. 

 Spiroloculina tenuis Egger. 1893, FG. p. 222, pi. i. figs. 46, 47. 



„ „ Heron-Allen & Earland, 1908, etc., SB. 1909, p. 310. 



