ATLANT. DEEP-SEA EXPED. 1910. VOL. Ill] 



PTEROPODA. 



17 



proposed by earlier authors, subject to doubt in some 

 cases (Boas etc.) though with positiveness in others (Monte- 

 rosato), while other investigators again (Munthe, Pelse- 

 neer, Meisenheimer etc.) warn us against this step. The 

 last-mentioned authors, however, all consider L. retroversa 

 as identical with L. balea, and their objections are based 

 principally upon the difference between L. balea and L. 

 trochiformls. A comparison of d and g in textfig. 15 

 (showing the original figs, by d'Orbigny and G. O. Sars of 

 L. trochiformis and L. retroversa) will, I think, remove 

 all doubt with regard to the identity of these two species. 

 Pelseneer's L. australis (copied in i, textfig. 15) also shows 

 in its shell all the characteristics of L. retroversa, while 

 the original L. australis of Souleyet is more like L. balea. 

 Geographical distribution. (See the chart, 

 textfig. 16). If I am right in my opinion about the 

 synonymy, L. retroversa seems to be widely distributed, 

 but restricted to the warm and temperate waters of the 

 Pacific and Atlantic Oceans. D'Orbigny records it between 

 28° N. and 34° S., EYDOUxand Souleyet "dans toutes les 

 mers", Boas from Malacca and Batavia, and Munthe from 

 the Atlantic and Indian Oceans at a latitude of about 30° S. 

 In the Mediterranean fauna it seems to be a very common 

 type (Philippi, Monterosato, Oberwimmer), and it has been 

 found along the Spanish coast (Locard), as far north as 

 the coasts of Ireland and England (Fleming, Forbes & 

 Hanley, Jeffreys, Gray) and even occasionally off Lofoten 

 on the Norwegian coast (G. O. Sars). 



sCL 



Fig. 16. Distribution of Limacina retroversa in the North Atlantic. The hatching 



represents area of distribution as known from previous investigations 



+ locality of capture during the "Michael Sars" expedition. 



Fig. 15. 



a. Heterofusus retroversus Fleming 1823, pi. 15, fig. 2. 



b. Scaea stenogyra Phil. 1844, pi. 25, fig. 20. 



c. Spinalis trochiformis Eudoux & Souleyet 1852, pi. 13, fig. 31. 

 d Atlante trochiforme d'Orbigny 1847, pi. 12, fig. 30. 



e. Spinalis flemingii Forbes & Hanley 1850, pi. 57, fig. 5. 

 /. — retroversus Jeffreys 1869, pi. 4, fig. 4. 



g. Q. O. Sars 1878, pi. 29, fig. 3. 



h. Limacina trochiformis Munthe 1887, fig. 8. 

 /. australis Pels. 1888, pi. 1, ftg. 6. 



During the "Michael Sars" expedition L. 

 retroversa was taken (about 800 individuals) at 

 St. 96 (50° 57' N., 10° 46' W.). 

 Date: 21 h 1910. 

 Depth: 50 m. 



Limacina balea Mailer. 



Limacina balea Mailer, 1841 (p. 490). 



Gray, 1850 (p. 33). 

 Spinalis Gouldii Stimpson, 1851 (p. 8). 

 Spiriale australe Eydoux & Souleyet, 1852, p. 222, 



pi. 13, fig. 20—26). 

 Heterofusus balea March, 1857 (p. 86). 

 Spirialis retroversus (pars) Jeffreys, 1869 (p 115). 

 Heterofusus balea Gould, 1870 (p. 505, pi. 27, fig. 349). 

 Spirialis balea Sars, 1878 (p. 329, pi. 29, fig. 2). 

 Limacina balea (pars) Boas, 1886 (p. 43). 



Munthe, 1887 (p. 5, fig. 5—7, not 1—4). 



— retroversa (pars) Pelseneer, 1888 (p. 27). 

 ■ balea Locard, 1897 (p. 25). 



— (pars) Posselt, 1898 (p. 254). 



— retroversa (pars) Meisenheimer, 1905 (p. 419). 



— balea (pars) Lenz, 1906 (p. 2). 



