OF THE LEYDEN MUSEUM. 185 



and are to be identified with i^Spirialis gouldi" Stiaipson. 

 Though Pelseneer (1888, p. 29) already pointed out, that 

 the specific distinctness of L. halea and L. retroversa could 

 not be maintained, yet they are separated again by Locard 

 (pp. 23 — 26), who on the other hand unites L. trochiformis 

 with L. retroversa, which certainly are distinct species. 



Furthermore I may draw attention to the fact, that a 

 very small lobe on the dorsal margin of the fin occurs in 

 all specimens, which lobe, as I have convinced myself, is 

 also to be found in typical specimens of L. retroversa, 

 from the coast of Norway. This lobe has hitherto not been 

 stated in this species; it has only been found in Limacina 

 helivina Phipps, L. antarctica Woodward and L. australis 

 Souleyet. Now, L. helicina is distinctly bipolar (see Meisen- 

 heimer, p. 7 and map I), L. antarctica is most likely 

 only a variety of this species in antarctic waters (Meisen- 

 heimer, I.e. p. 8). L. australis and L. retrovêrsa, both 

 with a raised spire, are respectively antarctic (notal) and 

 bipolar. This group, provided with the fin-lobe, shows thus 

 a clear tendency to the cold or temperate regions. The 

 Creseis virgida-acicida-group , considered by all recent 

 authors (except Schiemenz) to be the lowest Cavoliniidae, 

 and next related to the Limacinidae (viz. to such species 

 as are mentioned above) are strict inhabitants of tropic 

 and subtropic waters, at least they do not extend beyond 

 lat. 50° N. and 50° S. (with exception of a case mentioned by 

 Schiemenz, p. 14, where Creseis virgula has been recorded 

 from lat. 60° N. in the North-Atlantic). Perhaps this con- 

 sideration may be of some importance with respect to 

 phylogenetic speculations, especially because Meisenheimer 

 (pp. 73—86) clearly pointed out that the Pteropoda originally 

 are typical inhabitants of warm waters. 



Species 5. Limacina cochlostyloides, n. sp. 



(PL 7, Figs. 6—7). 



Empty shells : 



Indian Ocean (Gulf of Bengal), purchased 1907, 5 sp., Sowerby & Fulton. 



Notes from thie Leyden IMuseuin, Vol. XXIX. 



