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



Family Synopid^, Bovallius, 1886. 



In Dana's classification, 1852, the Synopinee are the third subfamily of the 

 Hyperidge ; Sjaence Bate, in 1862, made the Synopiades the first subfamily of the 

 Oxycephalidee ; Kossmann, in 1880, places the family Synopiadse in the tribe Hyperina ; 

 Bovallius, in 1886, named the family Synopidse, with the following diagnosis : — 



" The head is triangular, not tumid. 



" The eyes occupy the upper median part of the head, and are distinctly faceted. 



" The mandibles are well-developed, with a three-jointed palp. 



" The maxilUpeds, coalesced at the base, carry strong four-jointed palps. 



" The antennsB are fixed on the under side of the head. The second pair- are like 

 those of the Gammarids. 



" The seventh pair of pereiopoda are not transformed. 



" The uropoda are like those of the Gammarids. 



" The telson is cleft to the middle." 



According to Bovallius the Synopidse are the first family of a new tribe which he 

 names Amphipoda Synopidea, and in which he places two other families, named respec- 

 tively, Trischizostomatidse, Sars, and Hyperiopsidse. In my opinion the resemblance of 

 Trischizostoma (or rather Guerinia) to such genera of the Lysianassidte as Acidostoma 

 and Acontiostoma is far too close to permit of its separation from the Amphipoda 

 Gammarina (Gammaridea, Bovallius). I have alread)?- (p. 576) expressed a similar 

 opinion with regard to the Synopidse, and think that Glaus was quite right when, in 

 1871, he incidentally remarked that the genus Synopia belonged to the Gammarids. 

 If the tribe Synopidea be set aside, much of the diagnosis above given becomes super- 

 fluous, since what is said of the maxillipeds, the second j^air of antennae, the seventh 

 {our fifth) pair of peraeopods, and the uropods, does not require mention for an accepted 

 family of the Amphipoda Gammarina. On the other hand, the remnant of the diagnosis 

 would not sufiice to distinguish this family from the nearly related Syrrhoidse and 

 Pontoporeiidse ; I propose therefore to add the following characters : — 

 Upper Lip apically bilobed. 



Mandibles with the second joint of the palp broad, the third minute. 



First Maxillie with the inner plate small. 



Second Gnathopods not subchelate. 



First and Second Peraeopods with the third and fourth joints dilated. 



Whether the eyes are in reality faceted I am unable to say. 



