POEAMmiTEEA OF THE KERIMBA AECHIPELAGO. 737 



459 a. Amphistegina lessonii, var. gibba d'Orbigny. 



Amphistegina gibha d'Orbigny, 1826, TMC. p. 304. no. 6. 



mamillata d'Orbigny, 18-16, FFV. p. 208, pi. xii. figs. 6-8. 

 „ gibba Fornasini, 1903, AO. p. 144, pi. ii. fig. 4. 



1 Station. 



Several specimens of this plano-convex, or even concavo-convex (or " meniscoid"), 

 form were found at Stn. 11, which is the best Stn. for Amphistegina in all its 

 forms. This and A. madagascariensfs (q. v. sub A. lessonii) are the only ones of the 

 "eight so-called species" of Fornasini's note which it seems desirable for taxonomical 

 reasons to admit. It comes under the forms described by Brady as " still more 

 inequilateral, sometimes dome-shaped" (B. 1884, FC. p. 741, pi. cxi. fig. 7). Our 

 specimens are as pronounced as those figured (nt supra) by d'Orbigny in 1846 as 

 A. mamillata, and are identical with the type-specimens of A. gibha which we have 

 examined in Paris. 



Operculina d'Orbigny. 



460. Operculina ammonoides (Gronovius). 



Nautilus ammonoides Gronovius, 1781, ZG. p. 282. no. 1220, pi. six. (Fasc. iii. Tab. 2) 



figs. 5, 6. 

 Operculina ammonoides Carpenter, Parker, & Jones, 1862, IF. App. p. 310. 

 Brady, 1881, FC. p. 745, pi. cxii. figs. 1, 2. 

 Egger, 1893, FG. p. 434, pi. XX. figs. 38, 39. 

 „ „ Heroti-Alleu Ss Earlaud, 1913, CI. p. 147. 



Cusbman, 1910, etc., NP. 1914, p. 37, pi. xiv. fig. 7. 



2 Stations. 



Extremely rare; one large and typical specimen at Stn. 11 and two smaller ones 

 at Stn. IB. This species, so abundant in northern waters, appears to become very 

 rare in the tropics. Egger's records irom tropical localities depend in all cases on 

 a single specimen or so. Brady gives several localities in or near the tropics, but 

 do^s not mention the frequency of its occurrence. It is not uncommon in some dredgings 

 we have from off Cebu (Philippine Islands), but the specimens are all very small 

 compared with our British records. 



461. Operculina complanata (Defrance). 



LenticuHles complanata Defrance, 1822, Diet. Sci. Nat. vol. xxv. p. 453. 



Operculina complanata d'Orbigny, 182(5, TMC. p. 281. no. 1, pi. iv. figs. 7-10, Modele no. 80. 



Mii bins, 1880, FM. p. 104. 



Brady, 1884, FC. p. 743, pi. cxii. figs. 3-5, 8. 



Egger, 1893, PG. p. 435, pi. xx. figs. 40-42. 



Millett, 1898, etc., FM. 1904, p. 605 (References). 



Heron-Allen & Earland, 1908, etc., SB. 1909, p. 696. pi. xxi. fig. 4.. 



5 K 2 



