10 



KR. BONNEVIE. 



[REP. OF THE "MICHAEL SARS" NORTH 



decidedly distinguishes this genus from the earlier known 

 Limacinidae, — and points towards a relationship with the 

 family Cymbuliidae. 



Of this interesting genus one individual was found 

 during the "Michael Sars" Expedition, but, I am sorry 

 to say, without its shell, and with several other defects, 

 which make it impossible to give a satisfactory description 

 of the animal. The broad trumpet-like proboscis is so 

 unlike that of P. valdlviae Meisenheimer, that it will be 

 necessary to erect a new species, even if a complete 

 diagnosis of it cannot as yet be given. 



Procymbulia Michaelsarsi nov. sp. 

 PI. I, fig. 3. 



To the generic characters mentioned above I have 

 but little to add. The r a d u 1 a (textfig. 5), which is very 

 well developed, has the same characteristic appearance 

 as in Peraclis, with large spoon-shaped teeth, denticled 

 on one border (the lateral teeth) or on both (median 

 teeth). As in Peraclis, we find a small rudiment of a 

 tooth on both sides of each transverse row of the radula 

 [formula (1) 1 — 1 — 1 (1)]. The proboscis is different 

 from that of Peraclis, showing a dorsal and a ventral 

 lip united at both sides instead of the two lateral lips of 

 Peraclis, which are ventrally united. On this point our 

 species also differs from that of the "Valdivia" Expedition. 

 The colour of the proboscis is a very dark brown. 



In the single individual at my disposal the margin 

 of the swimming-plate was torn, and the same is true of the 

 mantle, so that important specific characters must be left 

 undescribed. 



Locality: St. 92 (48° 29' N., 13° 55' W.). 



Date: 23 / 7 — 24 /t 1910. 



Depth: 750 m. 



Limacina Cuvier. 



The main characters distinguishing this genus from 

 Peraclis are generally found in the semilunar oper- 

 culum, the indistinctly defined head with 

 asymmetrically developed tentacles, the development 

 of the foot into distinct lateral and median lobes, and 

 the asymmetry of the visceral ganglionic mass, 

 which is developed into a larger right and a smaller left 

 ganglion. A character distinguishing Limacina from Pro- 

 cymbulia and at the same time also from the families 

 Cymbuliidae and Cavoliniidae, is found in the dorsal 

 position of its pallial cavity. 



This may be true of all the earlier known typical 

 species of Limacina, but, as will be shown below, there 

 is one species (L. helicoides) for which the above named 

 generic characters must be modified in so far as on 

 several points it forms connections between Limacina and 

 other genera or families. 



Limacina helicoides Jeffreys. 



Limacina helicoides Jeffreys, 1877 (p. 338; pi. I, fig. 4 \\\ 



Pelseneer, 1888 (p. 23; pi. I, fig. 5). 

 Peracle „ Dall, 1889 (p. 80). 



Limacina „ Meisenheimer, 1905 (p. 8). 



Shells of this species have been brought home from 

 several expeditions ("Valorous", "Porcupine", "Travailleur", 

 "Challenger" and "Valdivia"), but always without animals 

 and in small numbers. It has therefore not been possible 

 to decide with certainty the affinities of this species within 

 the group of Limacinidae. 



During the "Michael Sars" Expedition more than 

 thirty individuals of Limacina helicoides of different sizes 

 were taken, all with complete animals. 



Fig. 6. 

 Shell of Limacina 



helicoides. 

 (From Pelseneer). 



Fig 7. Tentacles of Limacina helicoides. 



Description: With regard to the shell I have 

 nothing to add to the original description of Jeffreys 

 (1877, p. 335): Shell like a reversed Helix memoralis, 

 extremely thin, opaque, brittle, and glossy: sculpture, 

 a few delicate spiral striae, and close-set microscropic lines 





A 



B 



Fig. 8. Radula of Limacina helicoides. 



of growth: colour brownish-yellow: spire depressed, 

 not flat: whorls 4, rather convex: suture slight but 

 distinct: mouth irregularly and narrowly oval, rounded 

 on the outside, acute-angled above, and pointed below: 

 pillar twisted, furnished at its base a little way inside 



