420 • DISCOVERY REPORTS 



Almost universally distributed, but fading out at the deeper stations. It is often exces- 

 sively abundant, and, as usual, exhibits extreme variability, according to the nature of its 

 environment. Perhaps the best and most typical and regular specimens occur at WS 93. 

 Sessile individuals have been recorded at several stations, some show signs of having 

 been encysted. Abnormal and irregularly grown individuals are often very abundant. 

 At WS 246, a very curious and interesting specimen, consisting of an aggregated mass of 

 young individuals of varying sizes up to four to five chambers tightly bound together 

 occurs. It is apparently the contents of a reproductive cyst which has disappeared, as 

 the remains of an agglutinate covering are still visible. 



357. Truncatulina dispars, d'Orbigny (Plate XIV, figs. 32-34). 

 Truncatidina dispars, d'Orbigny, 1839, FAM, p. 38, pi. v, figs. 25-7. 



Twelve stations: 388; WS 71, 83, 86, 88, 91, 93, 95, 221, 225, 245, 248. 



The pretty little species which d'Orbigny described from the Falklands as frequent 

 ("mais pas rare") is fairly widely distributed in the gatherings, occurring not only on 

 the Continental Shelf but also in deep water. Structurally it appears to be nothing else 

 than a diminutive form of T. lobatula, but all the specimens are very typical ; they show 

 no sign of variation or of transition forms running into T. lobatula or T. iingeriana, 

 and it would therefore appear to be a true and constant local species. The best specimens 

 are at WS 71 and 88 ; at the latter station it is not uncommon. The Type could not be 

 found in Paris. 



Greatest diameter, about 0-30 mm.; height, o-o6 mm. 



358. Truncatulina variabilis, d'Orbigny (Plate XIV, figs. 36-39). 



Truncatulina ■variabilis, d'Orbigny, 1826, TMC, p. 279, no. 8. 



Truncafiilina variabilis, Brady, 1884, FC, p. 661, pi. xciii, figs. 6, 7. 



Truncatulina variabilis, Sidebottom, 1904, etc., BFD, 1909, p. 2, pi. i, figs. 5, 6; pi. ii, figs. 1-3. 



Twenty-three stations: 48, 51, 388; WS 71, 76, 83, 84, 86, 87, 88, 89, 90, 91, 92, 93, 97, 210, 213, 

 221, 225, 243, 246, 248. 



Very generally distributed and often very common. D'Orbigny 's species has no real 

 specific value. In the generality of specimens, the variability is merely an index to the 

 nature of the surface on which the animal has lived. This is best proved by the examina- 

 tion of sessile individuals which are quite common at some stations, notably WS 225 and 

 246. It will then be seen that the contour and arrangement of the chambers follows the 

 line of least resistance, as the protoplasm spreads itself out over the surface of attachment. 

 Disregard of this has led to the creation of what appears to us to be two unnecessary 

 genera, one, Cibicidella, Cushman, 1927, the genoholotype of which is stated to be 

 T. variabilis, d'Orbigny, though neither d'Orbigny nor the author state which of the 

 innumerable Soldanian figures represents the type (S. 1789, etc., T, 1789, i, p. 77, 

 pls.lxix-xciii). Later, in 1930, Cushman and Valentine have created a further genus 

 Dyocibicides, for those individuals in which the later chambers assume a roughly biserial 

 arrangement (C. & V. 1930, FSC, p. 30, pi. x, figs. 1-3). Such specimens occur in 

 numbers in the Falkland dredgings, notably at WS 76, 84 and 88. 



