186 BR. G. S. BKAUT OX NEW OR 



Pyrocypris cuierciii.'T; G. AV. Miiller. 

 Pyrocypris chierchia G. W, Miiller, torn. cil. p. 232, pi. xxv. figs. 1, o, C, jil. xxvi. figs. 12, 19, 



pi. xxvii. figs. 1, 2, 13, 14, 18, 24, 37. 

 Evpathistoma nutans G. S. Brady, ^w. cii!. p. 437, pi. xliv. figs. 21-26. 



Hah. Bay of Bengal : 'Galathea' Expedition, July 10th & 11 ih, 189C. 



This and other species oi Pyrocypris occur in immense numbers in tropical se;is, 

 and seem to contribute a very large share to the phosphorescence of those regions. 

 This has been noticed by many authors. Dr. G. W. Miiller notes that of P. chierchice 

 as many as twenty thousand individuals were taken in a single haul, and of P. revUU 

 fifteen thousand, and he attributes their light-producing faculty to the labial papillaj 

 which, so far as at present appears, are peculiar to this genus. 



Genus Philomedes Lilljeborg. 

 PiiiLOMEDES SORDIDA G. W. Miiller. (Plate XXIV. figs. 23-2G.) 

 Philomedes sordida G. W. Miiller, torn. cit. p. 237, pi. xxv. fig. 17, pi. xxvi. fig. 17, pi. xxvii. 

 figs. 28, 33. 

 Shell of the male (fig. 23), seen from the side, oblong-ovate, widest in the middle, 

 scarcely twice as long as broad ; anterior extremity narrow, rounded, without a beak, 

 antennal notch forming a wide and shallow sinus quite on the ventral margin ; 

 posterior extremity broader, well rounded ; dorsal margin well arched, forming an even 

 curve throughout its entire length ; ventral margin boldly arcuate from the antennal 

 notch to the posterior extremity: margins of the valves fringed at both extremities 

 ■with numerous closely-set setse, which extend in front on to the ventral and behind on 

 to the dorsal surface; right valve slightly overlapping the left in front: shell chitinous, 

 its surface marked with small closely-set subrotund pittings. Length 1-55 mm. 



The anatomy of the animal agrees generally with Philomedes, but the following 

 characteristic points may be noted :— The secondary branch of the antenna (fig. 24) 

 is extremely slender, the penultimate joint linear and bearing on its inner margin 

 two short setae, terminal joint dilated at the base, strongly curved and blunt, a long 

 seta at the base and a short one near the extremity; vermiform limb bearing very 

 few setae, armed at the distal end with three small claws at one side of the gape and 

 two on the other (fig. 25) ; postabdominal laminas (fig. 26) w^ith two large simple 

 basally-pectinated terminal ungues, followed twice by sequences of a short and a long 

 unguis, and finally three small sette. 



Hab. Cruz Bay. Three specimens, <S . Miiller's specimens were all females and 

 were taken off the north of Japan. 



Philomedes debilis, sp. nov. (Plate XXI. figs. 1-5.) 



Shell of the male, seen from the side, ovate, widest in the middle, width equal to 

 nearly two-thirds of the length (fig. 1); anterior extremity narrow, rounded, without a 



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