98 NILS ODHNER, NORTHERN AND ARCTIC INVERTEBRATES. III. OPISTHOBRANCHIA ETC. 



its sides covered with papillse, inost of wliich liave fallen off in the present specimens, 

 their marks sparsely set in approximately obliquely träns verse rows. The lateral 

 parts of the back slightly tubercled by the underlying liver; the median compart- 

 ment finely granulate. 



The rhinophores stout, of stretched-conical form, blunt-topped and granulate, 

 situated in the anterior margin of the back; their length 3 mm. 



The anterior right angle of the body is furnished with a small cutaneous lobe, 

 wliich sends ont a low hem, the ruclimentary mantle-margin(?), backwards. Behind the 

 middle (c. 10 mm. from the front) of the body there projects a larger leaf-like 

 lobe, which is finely granulate on its upper face, and shows a few minute branched 

 veins on the under side. On the left side of the body these appendages are wanting. 



Head strongly declining, produced at the sides into narrow triangulär lobes, 

 the upper margins of which start as low hems from the outside of the rhinophorial 

 bases. Their under margins are coalesced with the foot. Close by this margin runs 

 a swelling, which unites, under the mouth, with a similar one on the opposite side. 



On the right side there appears the genital aperture with the glans penis, which 

 is arched, flattened at the concave side, and unarmed. Farther back is situated the 

 anus, and, close by it to the right, porus renalis. 



Foot broad (5 mm.), rounded in front, with membrane-shaped side-margins, finelj^ 

 granulate on the upper side; the posterior end broadly rounded. 



Buccal organ lengthened (3,5 mm. in length, 1,5 mm. in breadth, 2 mm. in height), 

 strongly convex above, concave below. The lips very muscular and prominent, the 

 labial disc dilatecl in breadth and armed with radiating strips. 



Jaws lateral, 2,5 mm. in length, 1 Vs mm. in height, with convex upper margin 

 and concave under side, which forms a sliarp angle with the anterior one in front. 

 Mandibular process wanting. 



Radula 111, with 41 rows; the lam. lat. very thin and light yellow, con- 

 sisting of a rectangular base and a triangulär spine, which is denticulated in the inner 

 margin. The lam. med. are higli (0,2 mm.), strong and of a dark-broAvnish colour with 

 a broad median spine and below that a short blunt tubercle on each side. The basal 

 plate is quadrangular with rounded corners and is concave in the front to make up 

 for the tooth before it. Its under side has a transverse elevation. 



The bad state of preservation the specimens Avere in did not permit of a very 

 careful examination of the inner anatomy. 



From the bulbus pharyngeus emerges the slender oesophagus, in which opens 

 immediately a pair of lengthened salivary glands. The oesophagus widens to the 

 stomach, from the right side of which the intestine leads in a curve to the anus. 



The liver (fig. 1 1) fills the dorsal side of the posterior part of the bod}' and 

 sends out along each side to the rhinophores an anterior diverticle, the right one 

 being the larger of the two. It is divided up into a great number of small lobes, 

 which clo not enter into the papillae. The primary and secondary parts of the liver 

 have each a special ductus; the former open out into the posterior angle of the 

 stomach at the left side of the body, the latter farther forward. 



