120 G. O. SARS. CRUSTACEA. [norw. POL. EXP. 



right in referring it to his tribe Ampharthrandria, and it will unquestionably 

 also be found to belong to this tribe in the restriction here adopted, exhibiting, 

 as it does, no affinity whatever to either the Monstrilloida or Harpadoida, 

 whereas the Cyclopoid type is unmistakable. In general appearance, this 

 genus somewhat recalls that of Oithona, but in its structural details it dif- 

 fers to an extent that does not allow of its being included in the same family, 

 the new family Mormonillidce, established by Dr. Giesbrecht, being evidently 

 needed for lis reception. Dr. Giesbrecht records 2 species of this genus, viz., 

 M.phasma and M. minor, both taken in the Pacific Ocean south of the equator, 

 from great depths (1800 metres). The occurrence of a species of this genus 

 in the Polar Sea is of considerable interest, and, in order to ascertain the rela- 

 tion of this form to the 2 species described by Dr. Giesbrecht, I have subjected 

 the specimens to a very careful examination, without, however, having come 

 to a definite conclusion as to whether the polar form is or is not identical with 

 one of them. It seems to agree best with the species named by Dr. Giesbrecht 

 M. minor; but the agreement is not quite perfect, and, as the places where 

 these 2 forms were found are so widely remote, I prefer to describe the polar 

 form provisionally as a new species, leaving the ultimate decision regarding 

 the identity or non-identity of the two forms for future investigations. 



28. Mormonilla polaris, n. sp. 

 (PI. XXXIV). 



Specific Characters. — $. Body very slender, with extremely thin and 

 pellucid integuments. Anterior division oblong fusiform, slightly depressed 

 anteriorly, with the greatest width occurring rather in front of the middle; 

 anterior extremity, seen dorsally, obtusely truncate, posterior greatly attenuated. 

 1st pedigerous segment well defined from the cephaHc segment, and rather 

 large, exceeding in length the succeeding ones combined. 4th pedigerous 

 segment very slightly emarginated behind, and having the lateral corners 

 scarcely produced at all. Last segment of trunk not broader than the caudal 

 segment, and quite simple, without any trace of appendages. Tail, inclusive of 

 the caudal rami, somewhat exceeding half the length of the anterior division, 

 genital segment evenly rounded below, anal segment much larger than the 

 middle one. Caudal rami exceedingly slender and elongated, equalling in 



