33 



and may moreover be recognised by the relative length of the caudal rami, 

 by the shape of the incubatory pouch in the female, and, when examined in 

 the living state, also by the colour of the ripe ova. It may be, that Allman 

 has had before him specimens of this form, but as he has evidently combined 

 in his species IV. ascidicola several other very different forms, I agree with 

 Thorell in the discarding of the specific name proposed by that author. The 

 form recorded by Buchholtz from the Mediterranean under the name of N. 

 mediterranea I am unable to distinguish from the present species. 



Occurrence. I have met with this species in many different places on 

 the Norwegian coast, from the Christiania Fjord to Finmark (Hammerfest). 

 It occurs, often in considerable number, within the branchial cavity of several 

 kinds of simple Ascidians, being generally found attached by the aid of the 

 posterior antennae to the inner wall of that cavity. When losened from its 

 hold, the animal moves quickly about in the usual jerking manner observed 

 in most Cyclopoida; but very soon it again get hold of some other place. 

 Male specimens are much more scarce than female ones, and indeed among 

 the numerous specimens of this species collected, I have only succeeded in 

 finding 3 or 4 males. 



Distribution. Coast of Bohuslan (Thorell), British Isles (Brady), coast of 

 France (Canu), Mediterranean (Buchholz). 



2. Notodelphys rufescens, Thorell. 



(PI. XVII, 1). 

 Notodelphys rufescens, Thorell, 1. c. p. 35, PI. II, 2. 



Specific Characters. Female. Body comparatively a little more slender 

 than in N. Allmani, otherwise of a very similar appearance. Incubatory pouch 

 oval in outline, with the posterior extremity evenly rounded. Caudal rami 

 scarcely twice as long as the anal segment, and rather narrow, sublinear in 

 form, with the apical setae comparatively shorter and less divergent than in 

 A/. Allmani; bristle of outer edge more remote from the apex. Anterior 

 antennae almost exactly as in that species. Posterior antennae however com- 

 paratively less slender, with the terminal joint not nearly attaining the length 

 of the other 2 combined. Oral parts and natatory legs very like those parts 

 in N. Allmani. Last pair of legs likewise very similar, though having the 

 proximal joint comparatively less broad, and the distal joint of a more irregular 

 shape. 



5 Crustacea. 



