SYSTEMATIC 171 



only, and the edge of the mantle is strongly prolonged forward, as in the overarching margin of the 

 shell aperture, most characteristic of this species. The umbilicus was open, and the aperture wide and 

 oval. An operculum was obtained which did not agree very well with the only available figure (Souleyet, 

 loc. cit.), being rather more circular in shape. 



The depth distribution of inflata at this day-time station corresponds closely to what has also been 

 established (see below) for bulimoides. It shows its greatest day-time concentration at 50-100 m., 

 thinning out markedly below this level and also at the surface. 



Limacina bulimoides (d'Orbigny) 



1836 Atlanta bulimoides d'Orbigny, Voyage dans VAmerique meridionale, v, p. 179, pi. xii, figs. 36-8. 

 1852 Limacina bulimoides Souleyet, Voyage de la 'Bonite", Zoologie, II, 224, pi. xiii, figs. 35-42. 

 1888 Limacina bulimoides Pelseneer, Challenger Reports, XXIII, ii, p. 30. 



1904 Limacina bulimoides Tesch, Siboga-Exped. Repts. 27, iv, p. 13. 



1905 Limacina bulimoides Meisenheimer, Pteropoda, Wiss. Ergebn. D. Tiefsee-Exped. 'Valdivia', ix. 

 1946 Limacina bulimoides Tesch, Dana Reports, v (28), p. 9, fig. 5, pi. i, fig. 4. 



* Many empty. 



This species is one of the more abundant of tropical and subtropical Atlantic Limacinas, and its 

 general distribution has been discussed by Tesch (1946). Of the high-spired species of the genus, 

 bulimoides is distinguished from retroversa and australis by the oval aperture as distinct from the 

 quadrangular. The umbilicus is constricted as in retroversa, and almost imperceptible as Pelseneer 

 points out. From the subspecies balea, the taller form of retroversa, bulimoides is best distinguished 

 by the smaller number of whorls, which never reaches ten as in the mature balea. The shape of the 

 aperture is not always an easy character to interpret precisely: it may vary within a population with 

 the age of the individual. In typical adult females (1-9 mm.) in the Benguela material the columella is 

 always slightly concave towards the aperture; in earlier stages it may be straight or even convexly 

 curved to the left. A good distinction, however, from all the taller forms of retroversa is the absence 

 of a tentacular lobe on the anterior margin of the fin. From trochiformis , bulimoides is differentiated 

 by its larger size, the presence of an apertural beak and the relatively longer spire. As Tesch says, the 



