384 ARKIV FÖR ZOOLOGI. BAND 1. 



Spence Bate established tbe genus Euconaxius for the three 

 species with a "stylocerite" (a long spine) on the second joint 

 of the external antennse and a "scaphocerite" ("movable acicle", 

 or a long movable scale) inside of the stylocerite. To this 

 genus belongs, among others, as a real typical species, Axius 

 (Euconaxius) plecirorhyncus Strahl, as is clearly shown by 

 his fig. 4 1 , and it is now my intention to adel two species 

 to the genus Euconaxius. 



It seems to be a verv remarkable fact, that, on the whole, 

 the said shape of the external antenna? is also a characteri- 

 stic which marks Calastacus Faxon, as a different genus 

 from Calocaris. If it were not for the rudimentary eyes of 

 Calastacus, this genus would somewhat closely resemble Euco- 

 naxius, 



Euconaxius coronatus n. sp. 



The two specimens, belonging to the Swedish National Museum 

 of Natural History and mentioned below, were distinguished on their 

 label by the name Calocaris coronata. I therefore think it proper 

 to retain this specilic name. 



The carapace (Pl. 21, fig. 2) laterally compressed, its 

 dorsal side with the rostrum about twice as long as high on 

 the line of greatest height, terminating forwards in an acute 

 triangulär, narrowed rostrum, being spiniform and slightly 

 turned upwards at the tip (Pl. 21, fig. 3), armed along each 

 side with from 4 to 6 small acute teeth. From each of these rows 

 of teeth a lateral carina runs backwards, furnished with from 

 4 to 6 teeth, considerably larger than those on the rostrum. 

 Between the said carinse a dorsal carina extends for about two- 

 thirds of the length to the cervical suture, armed with one 

 or two spiniform teeth just behind the base of the rostrum. 

 Between the dorsal and the lateral earinae there is to be 

 found on each side a trace of a subdorsal carina, armed poste- 

 riorly with 2 or 3 teeth resembling those on the above-men- 

 tioned carinse. 



1 Strahl: "Ueber einige neue von Hrn F. Jagor eingesandte Thalassi- 

 niden" etc. "Monatsbericht d. Königl. Preuss. Akad. d. Wiss. zu Berlin 1861", 

 2te Häfte, Juli— Dec., S. 1060—1062, Fig. 2—4. 



