470 THE VOYAGE OF H.M.S. CHALLENGEE. 



that have heen described, even from widely-separated localities, the variation is very slight 

 indeed." See also Note on Streets, 1882. 



Anchylonyj;, new genus, is thus described : — " Head moderately large, broad and rounded 

 at the top, tapering inferiorly to the oral apparatus, and excavated in front. Eyes on the 

 lateral and dorsal surfaces of the head. Loth pairs of antennae present, long ; base of the 

 superior pair long and stout, three-jointed ; inferior pair slender, four-jointed. Flagellum 

 very attenuated and elongated. Thorax broad, somewhat compressed ; segments sis. 

 Abdomen narrow. The gnathopoda not subchelate, nor much reduced in size, when 

 compared with the following feet ; the first and second pairs of thoracic feet long, slender ; 

 carpus and meros linear. The third pair enlarged ; carpus and meros dilated, with the 

 anterior margin armed with teeth ; propodus flexes on the carpus, impinging against the 

 teeth on its anterior margin ; dactylus fused with the propodus. The fourth and fifth pairs 

 of feet subequal, shorter than the preceding. The three posterior pairs of abdominal 

 appendages biramous, lanceolate; rami pointed." In the additional observations it is 

 noted that " the mandibles are without appendages," and that, as in PJironima, " a pair of 

 wing-like plates exist at the base of the dactylus of both pairs of gnathopoda." 



The type species is Anchylonyx hamatus, but in 1882 Dr. Streets makes it a synonym of 

 Plironima elumjafa, Glaus, 1862, and PJinniiiiieUa elongafa, Glaus, 1872. 



Ancliyluinera thijropoda, Dana, is reported, with the additional observation that " the inferior 

 distal angle of the propodos of the third and fourth jjairs of thoracic feet is produced, and 

 when the joint is flexed this projection impinges against the antero-inferior angle of the 

 carpus." 



Platyscelus batei, n. s., is described, with the remark that " this species is closely related to 

 P. rissoinx; the differences are chiefly in the structure of the gnathopoda, and of the third 

 and fourth pairs of thoracic feet. The gnathopoda bear a striking resemblance to those of 

 the young of P. serraius, but as the rest of the structure of the animal shows no evidence 

 of immature development, this is undoubtedly their normal adult condition." Yet, as the 

 length is given as " .12 of an inch," and the inferior antennae are said to be short, the 

 specimen could scarcely bo full-grown, and the independence of the species is therefore very 

 doubtful. Platyscelus serraius, Bate, is regarded by Glaus as a synonym of Typhis oroides, 

 Eisso, and Platyscelus rissoinx as perhaps a synonym of his own Eutyplm armatus. Dr. 

 Streets' work does not seem to have come under the notice of Claus. Ampldpronoe 

 serrulata, n. s., is described, and Oxycephalns tidieixulatus, Sp. Bate, a species which Claus 

 identifies with Oxycephaly piseaior, Milne-Edwards. 



The new genus Leptocotis is thus described : — " Animal long and slender. Head large and 

 produced anteriorly into a rostrum ; narrowed behind the eyes ; the constricted portion 

 short, and not narrower than the thorax ; under surface excavated anteriorly on each side 

 for the reception of the superior antennre. Superior antennte short, sickle-shape. Inferior 

 antennaj five-jointed, folded upon themselves four times, and concealed beneath the head ; 

 first and second joints distally enlarged. An elongate mandibular appendage. Gnathopoda 

 short, and complexly chelate. Third and fourth pairs of thoracic feet having the coxae 

 dilated ; the fifth pair small. Fourth and fifth abdominal segments fused into one ; sixth 

 small. Caudal appendages long, biramous. Telson cylindrical, long." The type species, 

 Leptocotis spinifera, is described in detail. 

 This genus. Dr. Streets says, exhibits a remarkable blending of the characters of Oxycephalns and 

 Rhabdosoma. Much the same is said by Claus of his species Oxycepihalus fenuirostris, 

 1871, to which, in 1887, he makes Leptocotis spinifera, Streets, a synonym, without 

 explaining why he rejects the genus Leptocotis. Streets here speaks of " a long, acute 

 spine, pointing upward, on each side of the fifth " segment of the abdomen. In 1878, he 

 says nothing of this, but describes " the first three segments of the abdomen subequal, 



