1582 THE VOYAGE OF H.M.S. CHALLENGER. 



are constructed like the second but are smaller, the peduncle proper about half the length 

 of the telson. 



Telson long, lanceolate, very acutely pointed, reaching just beyond the first uropods, 

 the edges pectinate ; the length is about equal to that of the preceding double segment,- 

 to which it is itself firmly coalesced. 



Length. — The specimen, in the position figured, measured, in a straight line from the 

 tip of the rostrum to the back of the second pleon-segment, seven-twentieths of an inch. 



Localities. — Station 104, August 23, 1873; Equatorial Atlantic; lat, 2° 25' N., 

 long. 20° 1' W. ; surface to 100 fathoms ; surface temperature, 78°. One specimen, 

 female with eggs. 



Station 347, April 7, 1876; Equatorial Atlantic ; lat. 0° 15' N., long. 14° 25' W. ; 

 surface ; surface temperature, 82°. One specimen, with a shorter rostrum. 



Remarks. — The specimen above described is undoubtedly the same as Glaus' 

 Oxycephalies piscator. Claus gives for the synonymy of his species " O. piscator Edw., 

 Ann. scienc. nat. I.e. [xx. p. 396] 1830. O. oceanicus Guerin, Mag. de Zool. I.e. [t. vi. 

 CI. vii.] 1836. O. tuberculatus Sp. Bate, Catalogue of the spec. etc. 1862. O. tuber- 

 culatus Streets, Proceedings of the Acad, of Nat. Sciences of Phdadelphia 1878." It is 

 quite possible that the specimens referred to, or some of them, may belong to the present 

 species, but the evidence is defective. Guerin's species is apparently smooth-bodied and 

 is said to have the telson longer than the preceding segment ; in the Brit. Mus. Catal. 

 Amph. Crust., pi. liv., figure 3. s.t.u.z. is probably taken from Guerin and by accident 

 wrongly numbered as if belonging to Oxycephalus -piscator, M.-Edw. ; Milne-Edwards 

 does not say that his species is tuberculated, nor does he show the character of the 

 margins of the first three pleon-segments, a character which separates the species above 

 described from Oxycephalus edwarclsii, G. M. Thomson. Oxycephalus tuberculatus, 

 Spence Bate, is figured as though the margins of the pleon-segments were not excavate, 

 the fifth perseopods are stated to be rudimentary, not so long as the first joint of the 

 preceding pair, and the second uropods are said to have the margins of the rami smooth. 

 Under the circumstances it seems necessary to adopt the name Oxycephalus clausi, 

 Bovallius, both for the specimen here described and for those specimens which Claus has 

 named Oxycephalus piscator, since the diagnosis given by Bovallius for Oxycephalus 

 clausi is in essential agreement with the specimens in question, whereas the accounts 

 accompanying the earlier names either differ from these specimens or leave points 

 of importance undetermined. Bovallius assigns to Spence Bate's species from the Cape 

 of Good Hope, " rami of second pair of uropoda serrated," but this is probably only a 

 misprint for " not serrated." As the habitat of Milne-Edwards' species Bovallius gives 

 " Atlantic, Mediterranean, Indian Ocean, Pacific," while Milne-Edwards only says " Parait 

 avoir ete trouve dans l'ocean Indien." 



