54 



teristic of that genus, and as also a great similarity in the structure of the various 

 other limbs is found to exist between this and the preceding species. This form, 

 however, exhibits a rather different external appearance owing to the less pro- 

 nounced navicular form of the anterior division of the body, the complete absence 

 of any frontal crest, and the shortness of the anterior antennae. It is also of 

 far inferior size. 



Occurrence. A solitary, but well preserved, female specimen (the one here 

 figured) of this arctic form was found in a plankton-sample taken during the cruise 

 of the "Michael Sars" in 1900, at Stat. 34. As this Station is located within the 

 limits of the Norwegian Sea, the present Calanoid may properly be included in 

 the fauna of Norway. 



Distribution. Polar basin crossed by Nansen, in one place, north of 

 81 of latitude. 



Gen 14. SCOleCltliricella, G. 0. Sars, n. 



Syn : Scolecithrix, auctorum (part). 



Generic Characters. Body not very dissimilar in the two sexes, and of 

 comparatively short and robust form, with the anterior division more or less 

 strongly vaulted above, and very smooth, without any crest in front. Rostral 

 prominence bifurcate, each half tipped with a short, soft lappet. Last segment of 

 metasome united with the preceding one, and having the lateral parts rounded 

 off. Urosome comparatively small, especially in female. Caudal setse not much 

 elongated, and subequal. Anterior antennae in female rather slender, 22-articulate, 

 the last 2 joints being confluent, in male transformed in the usual manner. 

 Posterior antennae with the outer ramus longer than the inner. Mandibles with 

 the masticatory part but slightly expanded, inner ramus of palp well developed, 

 though smaller than the outer. Maxillae and posterior maxillipeds about as in 

 Amallophora. Anterior maxillipeds, however, with all the terminal appendages of 

 the same appearance, vermiform. Oral parts in male slightly transformed. Natatory 

 legs remarkably elongated, resembling in structure those in Amallophora; terminal 

 spine of outer ramus, however, not serrate, but very minutely denticulated outside. 

 Last pair of legs present in both sexes, in female very small, uniarticulate, lamellar, 

 with 2 comparatively short spines inside the tip; in male considerably produced, 

 right leg the longer and carrying at the end of the 2nd joint a styliform appen- 

 dage, left leg simple, with the 1st joint conspicuously dilated distally. 



