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



HETEROPODA. 



15 



Firoloida. 



In species belonging to this genus the tail is rudi- 

 mentary. The males have a pair of tentacles ahead 

 of the eyes, and a sucker at the border of the swim- 

 ming fin. 



Firoloida desmaresti, Lesueur. 

 (PI. V, figs. 60—66). 



Eyes cylindrical, their total length more than twice 

 the diameter of the lens (fig. 64). 



Nucleus irregulary spherical or pearshaped, with the 

 rudimentary tail protruding beneath its ventral side (figs. 

 61-62). 



Cutis transparent and quite smooth, without spots, 

 spines or tubercles. 



The svimming fin is large, subspherical, its dia- 

 meter being about three times the width of the body. The 

 sucker of the male is placed on its anterior border (fig. 

 60, 63). 



The radula carries about 25 rows of teeth. The 

 median plate of each has its spines (three small spines 

 on each side of a large one) secluded between the large 

 sickle-shaped side -- pieces of the plate. Intermediate 

 plates have no secondary spines at their free ends. 

 Lateral plates sickle-shaped, nearly as long as the inter- 

 mediate ones (fig. 66 a — b). 



The males carry a pair of tentacles protruding 

 from the forehead close to the base of the eyes (fig. 65) 

 a sucker on the anterior border of the svimming fin 

 (fig. 63) and a pair of fingershaped appendages protru- 

 ding from the anterior side of the nucleus, each of 

 them containing a dark, more or less spherical, body l ) 

 (fig. 62). 



In the females (figs. 61, 64) all these structures are 

 lacking, but in a number of individuals we find a long 

 egg-chord, by thin walls divided into chambers, in which 

 the eggs are placed (fig. 61). 



Locality 



Depth 

 metres 



Dato 

 1910 



Number of 

 individuals 



Size 



St. 



Lat. N. 



Long W. 



mm. 



19 



36° 5' 



4° 42' 







May 2-3 



11 </ 



10-25 



46 



28° 56' 



21° 45' 







. 29 



-1 ? 



11—25 



47 



29° 2' 



22° 53' 







. 30 



5 cf 



ca. 10 



48 



28° 54' 



24° 14' 







„ 31 



4 d" 



ca. 20 



49 



29° 8' 



25° 16' 



1000(?) 



July 1 



1 ? 



20 



56 



36° 53' 



29° 47' 







„ 10-11 



(5 2 



18—30 

 12—20 



« 



— 



— 



150(?) 



— 



f2 ? 

 \2 </• 



17—20 

 12—13 



J ) The fixation of my material does not allow of any discussion 

 concerning the special meaning of these peculiar structures, which 

 probably form parts of the copulatory organ. 



