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U.,S. NATIONAL MUSEUM BULLETIN 271 



maxillipedal palp, and have the first maxillary palp reduced in size. 

 The unique species of lafystiid, however, has retained the subchelate 

 condition of its second gnathopod, although it is feeble. 



The uniformity of the Laphystiopsidae is complicated by the loss 

 of the rostrum in Prolaphystius and that genus warrants further in- 

 vestigation on its familial assignments. Prolaphystius has an elongate 

 urosomite 1 like Podoceridae but othermse bears no resemblance to 

 that family. It has been included in the key to Calliopiidae where it 

 seems to have strong affinities. 



The Astyridae bear a small accessory flagellum and broadly sepa- 

 rated outer lobes on the lower lip. 



The Oedicerotidae warrant close inspection of their slightly sub- 

 chelate gnathopods as a feature distinguishing them from laphysti- 



FiGURE 111. — Laphystiopsidae: Laphystiopsis planifrons Sars (1895, pi. 135): a, lateral; 

 h, upper lip; c, mandible; d, lower lip; e,i, maxillae 1, 2; g, maxilliped; h,i, gnathopods 1, 2; 

 y, uropod 3; k, telson. Prolaphystius isopodops K. H. Barnard (1930): /, head, right side, 

 stippled; vi, maxilla 1; n, mandible; o, telson. 



