36 DR. R. V. WILLEMOES-SUHM ON SOME ATLANTIC 



The palpus of the first maxilla (2) and the free dorsal shield (1) are hoth characters 

 which, among Schizopods, we only find in Nebalia, a genus which has hitherto had a very 

 isolated position, and was considered a connecting link hetween these and the Phyllopods. 

 In Plate VI. fig. 9, we have figured the first maxilla with its long palpus in our Nebalia 

 longipes. The palpus there is a mere continuation of the maxilla ; here, however (where 

 it has very little resemhlance to the Nebalia palpus), it seems to he in articulation 

 with the maxilla. This is a character which I have hitherto only found in Gnathophausia, 

 and confirms my opinion that this genus is, next to Nebalia, the most aberrant one among 

 the Schizopods. 



In Lophogaster as well as in Gnathophausia the dorsal shield is of a parchment-like 

 consistency. In the former its posterior and lateral edges are free, hut the rest of the 

 shield forms the integument of the pereion- segments. A free dorsal shield has hitherto 

 never been found in a true Schizopod, but is also peculiar to Nebalia. Now Nebalia is 

 considered to be an aberrant Schizopod with nine abdominal segments ; and it seems to 

 me to be very interesting for the explanation of the semidivision of the last pleon-segment 

 in Gnathophausia, that this genus has two other phyllopodal characters, in the configura- 

 tion of its dorsal shield and the presence of a palpus on the first maxilla ; but in all the 

 main points Gnathophausia is much more a typical Schizopod than Nebalia, and, I think, 

 not even closely allied to it. Probably both derive tbeir origin from a series of animals 

 which were neither Schizopods nor Phyllopods, and to which possibly belonged the fossil 

 forms Dithyrocaris, Ceratiocaris, &c. I do not know how far these forms are really allied 

 to Gnathophausia, as I have not the literature on them on board ; but I strongly suspect 

 that also on them some light may be thrown by the discovery of this interesting genus. 



The Characters of the Lophogastridce, 



therefore, ought to be modified in several points ; the following characters ought to be 

 added to the family-description : — connexion of the shield with the segments of the pereion 

 complete or incomplete ; with or without accessory eyes on the second maxilla ; with or 

 without a palpus on the first maxilla ; and with or without subjoints in the pereiopods. 

 Besides, all the family characters given by Sars are applicable to both genera. 



Characters of the Genus and, Species. 



Gnathophausia*, n. gen. 

 Carapace in no connexion with the five posterior segments of the pereion ; a long 

 rostrum ; first antennae with a short and stout pedunculus and two flagella, a long and 

 a shorter inner one ; second antennae with an oblong squamiform appendage ; stout 

 mandibles, with a three -jointed palpus; a palpus on the first maxillae; accessory eyes, 

 palpus, and flagellum on the second maxillae; maxilliped showing nothing particular. 

 First gnathopods terminated by a claw ; all the gnathopods and pereiopods leg-like, the 

 latter showing subjoints on their penultimate joint. Six pairs of gills at the base of the 

 gnathopods and the four anterior pereipods ; two branches of the arborescent gills laterally 



* From yydOos and cjxivo-ios. 



