10 NILS HJ. ODHNER 



coming from the lobes situated here. In the Holohepatica the 

 right liver lobe is replaced by a „pancreas," or gall bladder, 

 with its separate opening into the stomach. This coecum is 

 according to Pelseneer (1894, p. 43)'^ „l'homologue du foie droit 

 des Tritoniens et des larves d'Eolidiens", and is, consequently, 

 also the homologon of the right liver lobe or lobes of the 

 Giadohepatica. While, in he Holohepatica, the right larval liver 

 has been transformed into a „pancreas'', it has, in the Giado- 

 hepatica, developed in the same manner as the left lobe, but has 

 in Tritonia, exceptionally, been subjected to a secondary coale- 

 scence with the left liver mass, and got a common opening 

 with this. 



With regard to the affinities in two directions which the 

 family in question exhibits, it is most convenient to classify it 

 according to Pelseneer. It must, however, be remarked that 

 his tribe Tritoniomorpha is rather a heterogenous group which 

 has as a common character only the primitiveness of their 

 organization in relation to the more speciahzed Nudibranchs, 

 but which otherwise contains greatly differing types, showing a 

 beginning differentiation in the same directions as the perfected 

 higher Nudibranchs. In this respect the family Goniaeolididae 

 is of a special interest; it was established by me in 1907, and 

 classified together with the Tritoniidae, a position which has 

 been verified by a renewed investigation given in the following 

 pages. 



Fam. Goniaeolididae. 



In my work of 1907 this family was established to com- 

 prise the genus Goniaeolis created by M. Sars for the single 

 species G. typica described by the same author. This species 

 and genus had been misinterpreted by Bergh, who, in 1886 ^ 

 applied this specific name to a different type, a true member 



^ Recherches sur divers Opisthobranches. Mém. cour, et mém. des savants 



étrangers. Acad. Roy. de Reigique, T. LUI. Rruxelles. 1894. 

 ^ Bijdragen tot de Dierkunde. 13. Amsterdam. 



