452 FROCEEDINOS OF THE NATIONAL MUSEUM. vol. xxxiii. 



NOGAGUS ERRANS Kroyer. 



Noijagus errans Kroyer, 18G3, p. 173, pi. x, fig. 3 a to /?. 



This species is based upon a single specimen captured in a tow-net 

 wliile swimming freely at the surface in the Atlantic Ocean near Porto 

 Santo. At the close of his description Kroyer states: "It is clear 

 that this animal, in spite of its four free thorax segments, differs sig- 

 nificantly from Nogagus forms in the shape of the rostrum, the pres- 

 ence of a furca, the rudimentary condition of the endopod of the first 

 legs, and the absence of this ramus in the fourth legs. Conse(|uently 

 it forms a connecting link with the Caliginge, but does not belong to 

 any of the established genera in that group, as far as I can see. 



It would therefore be justifiable to make of it a new genus, but I 

 am not so inclined on account of the scarcity of material (only one speci- 

 men), and so will leave it for the present under Nogagus." This 

 species evidently belongs to the Euryphorinx instead of the Pan- 

 darinse, and is closely related to Dysgamus, Euryphorus, and especially 

 to the new genus, Dissonus, recently established by the present 

 author upon material obtained from Ceylon.'^ It certainly does not 

 belong to any of the Nognus types here established, and consec|uently 

 should not, even temporarily, find shelter in the much-abused genus 

 " Nogagus." 



DINEMATURA GRACILIS (Nogaus male) Burmeister. 



Dincvintura gracilis Burmeister, 1833, p. 284, pi. xxiii, fig. 1. 

 Nogagus gracilis Milne Edwards, 1840, p. 400. 



This species was first described b}" Burmeister under the name 

 Dinematura, in the belief that it was a male of that genus. Milne 

 Edwards changed the name to Nogagus, but without giving any 

 reasons for so doing, and without adding anything in the way of 

 description. Frey and Leuckart, m their large work on the Wir- 

 belloser Thiere, published in 1847, examined other specimens of this 

 species and say of them (p. 166), that they could only find two seg- 

 ments in the abdomen instead of three as reported by Burmeister. 

 The terminal segment show^ed a median posterior incision, and ap- 

 peared to be made up, through the contraction of the basal joints of a 

 pair of legs metamorphosed into swimming lappets; each of the 

 latter was armed with four seise instead of three. The posterior 

 lobes of the carapace were longer and narrower than in Burmeis-ter's 

 specimen, and overlapped the follow^ing segment, whose lateral lobes 

 were only feebly developed. At the close of his description Bur- 

 meister declares that he has but a single specimen, taken from a 

 Squalus acanthias. And he can not, therefore, affirm with certainty 



aHeport to the Government of Ceylon on the Pearl-Oyster Fisheries, Supplementary 

 Report, XXXIV, p. 198, pi. iii. 



