THE COPENHAGEN MUSEUM AND OTHEK SOUKCES. 427 



Phreatogamjiarus, n. g. 



Without eyes. Upper lip broader than deep. First joint of mandibular palp not 

 very short. Pirst and second gnathopods equal. First and second perfeopods much 

 shorter than third. Fifth peroeopods the longest, with sixth joint much longer than any 

 of the other joints. Thii'd uropods long, with equal, one- jointed, cylindrical rami. 

 Otherwise like Gammarus. 



The generic name means a well- Gammarus. 



The type-species is Phreatogammarus fragilis (Chilton), 1882, from wells in New 

 Zealand. 



Ommatogammartjs, n. g. 



Near to Gammarus. Dorsal spines only on fourth to sixth pleon-segments. Eyes of 

 irregular form, with indented outline. First antennfe longer than second, but usually 

 with shorter peduncle; accessory flagellum of more than one joint. Upper lip narrowed 

 to a rounded apex. Under lip with inner lobes i-udimentary. Third joint of mandibular 

 palp not very elongate. First maxillse having inner plate fringed with numerous sette, 

 outer carrying eleven spines ; second joint of palp with about ten spine-teeth on one 

 maxilla, and short spines on the other. Maxillipeds with outer plate reaching far along 

 second joint of palp ; spine-teeth and setae numerous. Hand of iirst gnathopods not 

 smaller than that of second. Third uropods having outer ramus about twice as long as 

 inner, with simple setse on its inner margin ; inner ramus with feathei'ed setse on both 

 margins. Telson cleft to the base. 



The generic name alludes to curious character of the eyes. 



The species included are : — Ommwto^amwzarM^ ff/6^»«s (Dybowsky), 1874 ; 2. O.Jlacus 

 (Dybowsky), 1874 ; 3. O. carneolus (Dybowsky), 1871 ; 1. 0. amethysfimts (Dybowsky), 

 1874 ; all from Lake Baikal. 



Odontogammarls, n. g. 



In general like Gammarus, but lower front angle of fifth side-plates produced into a 

 tooth ; jieduncle of first antennse not shorter than that of second, its third joint as long 

 as its second ; hand of first gnathopods not smaller than that of second ; third to fifth 

 perseopods having second joint produced at lower hind angle into a tooth ; third uropods 

 not very long, but, as in Gammarus, the tAvo-joiuted outer ramus longer than the inner. 



The generic name alludes to the tooth on the fifth side-jilates. 



The species included are Odontogammariis calcaratus (Dybowsky), 1874, and 0. mar- 

 garitaceus (Dybowsky), 1874, both from Lake Baikal. 



SECOND SERIES. — ZOOLOGY, VOL. VII. 59 



