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



HETEROPODA 



nanus from the "Michael Sars" Expedition, sections oi 

 which have proved them to be immature, as representing 

 only young stages of the challenged variety of C. la- 

 marckl. In this case the darkly pigmented extension on 

 the dorsal side of the tail, described and figured by 

 Vayssiere, may be considered identical with the ventral 

 extension in young individuals of our form, its dorsal 

 position being due to a twisting of the body of the 

 specimen described by Vayssiere, a supposition which, 

 after a look at his illustration (1904, PI. VI, fig. 83), does 

 not seem improbable. 





Locality 





Depth 



metres 



Date 

 1910 



Number of 

 individuals 



Size 



St. 



Lat. N. 



Long. W. 



mm. 



39 A 



26° 3' 



15° 0' 



120 



May 20-21 



1(?) 



2,5 



45 



28° 42' 



20° 0' 



100 



„ 28-29 



2 



10 



51 



31° 20 7 



35° 7' 







June 5-6 



2 



10-30 



52 



31° 24' 



34° 47' 







, 6-7 



3(?) 



18-20 



56 



36° 53' 



29° 47' 



50 



„ 10-11 



1+3 



40, 15-20 





— 



— 



100 



— 



4 



10-12 



» 



— 



— 



150 



— 



1 



12 



Cardiapoda, d'Orbigny. 

 Carinariidae with a spiral shell covering only a 

 small part of the nucleus, the peduncle of which is 

 more or less obviously directed backwards. Appearance 

 of sucker on the swimming fin variable. 



Cardiapoda richardi, Vayssiere. 

 (PI. II, figs. 26—27). 



Body cylindrical, with an abruptly cut trunk, and 

 with the peduncle of the nucleus directly continuing the 

 body behind, running parallel with the tail. The latter 

 rapidly tapers and forms at the end a long thread-like 

 appendage. It carries along its whole length a narrow 

 dorsal fin, and on the ventral side a pair of horizontal 

 folds forming together a pair of claspers (Cb), like 

 those found in young specimens of Carlnarla. 



The spherical nucleus has at its posterior border small 

 spiral appendage, and at its anterior border 7 — 8 gills. 

 It is carried by a peduncle directed backwards, and con- 

 nected to the tail by means of a cutis stripe, which farther 

 back forms the dorsal fin of the tail. 1 ) The swimming 

 fin is broadly oval, with coarse muscle bundles crossing 

 each other in two directions, and without a sucker. 



The eyes are large and the tentacles short and 

 pointed, with a broad base. 



The proboscis forms a direct continuation of the 

 trunk, though slightly constricted before eyes. It does 

 not taper in front, but is abruptly cut and with the mouth 

 opening dorsally. 



The radula (fig. 27) has median plates with 

 three spines, the one in the middle considerably larger 

 than the lateral ones; these spines are so tightly packed 

 that they might be considered as one spine with three 

 points. The intermediate plates have at their free 

 ends one spine overwhelmed by a short and blunt hook. 

 The lateral plates are nearly as long as the inter- 

 mediate ones. 



The skin is smooth and (in the fixed animal) brow- 

 nish in colour, translucent, but not transparent as in 

 Carlnarla. Small oblong cuticular spots are seen equally 

 spread all over the body. 



One specimen, 12 mm. in length (measured between 

 the front end and the posterior border of the nucleus). 



Locality 



Depth 

 metres 



Date 1910 



Number of 

 Individuals 



Size 



St. 



Lat. N. 



Long. W. 



mm. 



52 



31° 24' 



34° 47' 



50 



June 6-7 



1 



12 



') Near the base of the nucleus there are in the specimen at 

 hand two peculiar thread-like appendages diverging from points at the 

 right side of the peduncle. The meaning of these appendages is 

 unknown. 



Ptero tra che/dae. 



Heteropods without a shell. The spindle- or 

 pear-shaped nucleus embedded in the body at or near 

 the posterior end of the animal. 



This family includes the two genera Pterotmchea 

 and Flroloida, both of which are represented in the 

 material from the -'Michael Sars" Expedition. 



Pterotrachea, Forskal. 



In this genus the body is continued behind 

 the nucleus, forming a laterally compressed tail, which 

 gradually diminishes in vertical extension towards the 

 posterior end. No tentacles. The males have a sucker 

 at the edge of the swimming fin. Two longitudinal 

 rows of buccal teeth are found in the palate. 



I fully agree with Tesch (1906) in his lament with 

 regard to the distinction of species within this genus. 

 The task of identifying new material with previously 

 described species is not only a difficult and time-wasting 

 one, but is in many cases absolutely impossible, most of 

 the old descriptions and figures referring to generic 

 characters only. Endeavours to unravel the synonymy 

 of the described species of Pterotrachea can therefore be 

 of very little scientific value; the only way of reducing 

 the chaos to order will be to leave out of consideration 

 all forms insufficiently described which can not be subjected 



BONNEVIE — 11 



