386 



Gen. 2. Laphystiopsis, G. 0. Sars, n. 



General form of body somewhat resembling that in the genxis Laphy- 

 slim, being distinctly depressed. Ceplialon produced in front {o- a broad 

 spatnlate lamella covering tbe bases of the antennee Coxal plates very 

 small, none of them angularly produced. Epimeral plates of metasome much 

 as in Laphysthis. Eyes quite rudimentary. Both pairs of antennae very 

 slender and elongated, the superior ones much the longer. Buccal area but 

 little projecting below, and having the oral parts feebly developed. Anterior 

 lip very broad, transverse, with a small incision in the middle of fhe terminal 

 edge; posterior lip with distinct, though small inner lobes. Mandibles not 

 very strong, cutting part but little projected, and obliquely truncated at the 

 regularly-dentated tip, molar exj)ansion distinct, flap-shaped, palp very slender. 

 First pair of maxillae with the palp rather large, though only composed of 

 a single joint, masticatory lobe comparatively narrow, with few apical spines, 

 basal lobe small, iinisetose. Second pair of maxillae very small, with the 

 lobes nearly equal-sized. Maxillipeds of normal appearance, though rather 

 small, both the basal and masticatory lobes poorly developed, palp of the 

 usual structure, 4-articulate. Both pairs of gnathopoda quite simple and of 

 the very same structure, but little differing in their ajipearance from the 2 

 anterior pairs of jiereiopoda. The latter comparatively less strong than in 

 LapJiysHns, the 3 posterior pairs successively increasing in length, and having 

 the basal joint laminarly expanded. Branchial lamellae rather large. Uropoda 

 with the rami lanceolate and edged with small denticles, last pair rather 

 differing from the preceding pairs, having the basal part very short, and the 

 rami more foliaceoiTs in character. Telson simple, sqiiamiform. 



Bemarlis. — As seen from the above diagnosis, the present new genus 

 exhibits some very striking differences from the genus Laphystins, especially 

 as regards the structure of the oral parts and the gnathopoda. But in other 

 respects it is evidently nearly related to that genus, and ought therefore, in 

 my opinion, to be placed in the same family. It comprises, as yet, only 

 a single species, to be described in the sequel. 



2. Laphystiopsis planifrons, G. 0. Sars, n. .sp. 



(PI. 136). 



Body comparatively^ slender, and distinctly depressed in its anterior 

 part, with the segments sharply defined by rather deep transverse depres- 

 sions ; last segment of metasome provided dorsally with a compressed gibbous 



