26 



NILS ODHNRR. NORTHERN AND ARCTIC INVERT!? BRAT BS [II. ( »PISTHORR ANCH1 A BTC. 



AnciiLi Loven 1846. 



Rhinophores kneed, long, the upper half laminated. Colour white, transparent, 



ends of the appendages yellow. L. 18 mm. A. cristata (Alder 1841). 



PI. Ill figs. 16—17. 



Fam. Aeolididae. 



I. Dorsal papilla? mostly with cnidocysts, simple, not ramose nor furnished with a 

 cutaneous membrane; no crista between the rhinophores. 



A. Radula 0.1.0, the teeth horseshoe-shaped, usually not produced to a strong 

 spine; papillae in regular transversa] rows; rhinophores simple, not laminated; 

 penis unarmed. 



1. Mandibular margin smooth; papilla? more or less compressed; teeth of the 

 radula very broad, semilunar, with pectinated margin. Foot with lateral 

 angles in front or with short triangular lobes (subfam. Aeolidina?). 



a. Teeth of the radula uniformly arched Aeolis Cuvier. 



Teeth of the radula incised in the margin Aeolidiella Bergh. 



2. Mandibular margin denticulated; papilla? subcorneal (subfam. Cratenina?). 

 a. Papilla? in densely set rows; anus lateral; foot more or less rounded 



in front; mandibular margin with one row of denticles. 

 + . Teeth of the radula with marginal spines of varying size; foot broad, 

 rounded in front; head broad Cuthona Alder & Hancock. 



+ +. Teeth of the radula with the margin pectinated (spines of uniform 

 size); foot shortly lobated in front; head of usual breadth 



Cratena Bergh. 



//. Papilla' in Clusters: foot with produced angles; anus latero-clorsal, 



+ . Mandibular margin with many rows of denticles Cuthonella Beruh. 



+ +. Mandibular margin with one row of denticles Hervia Beruh. 



B. Radula 1.1.1 with the central teeth produced in a strong spine ; papilla? in 

 rows on regular obliquely - transverse ridges; rhinophores smooth; penis 

 unarmed, furrow-shaped; female genital aperture with a pair of aculeated 

 cushions (subfam. Cumanotina?). 



Mandibular margin with one row of denticles; teeth of the radula dentated; 

 oral tentacles papilla-shaped: head much expanded laterally; anus latero-dorsal 



Cumanotus n. sp. 



C. Radula 1.1.1 or 0.1.0 with the central teeth produced in a spine; papilla? 

 mostly in clusters, in longitudinal series or in irregular transverse rows; penis 

 armed or not. 



1. Rhinophores simple, rarely laminated. 



a. Anus latero-dorsal; papilla? clavate or inflated: foot rounded or with 

 produced anterior angles (subfam. Tergipedina?). 

 + . Radula 0.1.0. 



a. Penis unarmed ; no glandula? ptyalina?. 



*. Papillae in one row on each side, inflated: foot rounded in front: oral tentacles 

 present : mandibular margin denticulated Tergipes Alder & Hancock. 



**. Papillae in many longitudinal rows, inflated: foot with tentacle-shaped produced 

 anterior angles; teeth of the radula united to a serrated band: mandibular margin 

 smooth: no cnidocysts Forestia Trikchese. 



