A. R. MOLANDER, TWO NEW SPECIES OF DECAPODS. 3 



the Spirontocaris Gaimardi very often and in certain regions 

 carry a spina on their third abdominal segment (= Hippolyte 

 Gibba Kröyer). A similar spina is also found on the third ab- 

 dominal segment on the investigated specimens of the Spi- 

 rontocaris recurvir ostris, which also has their epimera very 

 strongly developed. It appears to me that these features 

 may only be sexual distinctions, which will not be found 

 on the other sex of this species. 



Spirontocaris recurvirostris is closely related to Spironto- 

 caris Gaimardi and Spirontocaris Fabricii, particularly to the 

 latter. Spirontocaris Fabricii is exclusively a littoral animal 

 along the westcoast of Greenland, whereas Spirontocaris re- 

 curvirostris and also S. Gaimardi and S. polaris are found at 

 greater depths. S. recurvirostris belongs to deeper regions 

 than any other species of the genus Spirontocaris in the 

 westcoast of Greenland. 



Spirontocaris recurvirostris like S. groenlandica (Fabr.), S. 

 Fabricii (Kröyer), S. macilenta (Kröyer) and S. microceros 

 (Kröyer) belongs to a western American group of the genus 

 Spirontocaris. 



Synopsis of the Spirontocaris Spence Bate. 



A. The base of the rostrum without spina över the orbits. 



1. Rostrum as long as the scaphocerit or longer. 



a. Rostrum slowly tapering to a fine point. 



*. Rostrum straight, generally with teeth 



S. Gaimardi M. Edwards. 

 **. Rostrum curved 



f . The upper edge of the rostrum with one tooth 



at the base S. Fabricii Kröyer, 



tf. The upper edge of the rostrum with two or 



three teeth S. recurvirostris n. sp. 



b. Rostrum with a broad, obtuse point, the lower edge 

 with a few teeth S. macilenta Kröyer. 



2. Rostrum shorter than the scaphocerit. 



a. Rostrum without a bifid apex S. pusiola Kröyer. 



b. Rostrum with a bifid apex S. cranchi Leach. 



B. One spina över the orbits at the base of the rostrum. 

 1. The upper edge of the rostrum with 4 or 5 teeth 



S. polaris Sabine. 



