196 Mr. G. A. Boulenger on a new Siluroid tish. 



5. On -a Hermaphrodite Example o/Mytiliis modiolus. 



In examining a series of ' horse '-mussels from Stream 

 Sound, East Burra, Shetland, in February (5th), a specimen 

 measuring 4^ inches was observed to be peculiar. It had a 

 somewhat small ovarian region chiefly developed in front of 

 the posterior adductor, as far as the byssus, and of a tint less 

 bright than usual. In front of the byssus the foot was 

 enlarged and formed a somewhat crescentic elevation of a 

 pale yellowish hue, with a free portion of the foot behind. 



On section the ovary — extending, as just mentioned, as far 

 forward as the byssus — presented numerous ova, but also a 

 large amount of degenerating tissue and cells, with reddish- 

 brown bodies and debris, as in the ovary of Mytilus edulis 

 during the period of absorption after spawning. 



The enlarged region of the foot showed a uniformly minute 

 cellular structure, as in the testis of a male. The cells indeed 

 closely agreed with the sperm-cells, only the mass seemed to 

 have a larger amount of connective tissue. 



The mussel had formerly received an injury to the left 

 valve posteriorly, but it had been repaired. 



XXVITI. — Description of a new Silur aid Fish from Burma. 

 By G. A. Boulenger, F.R.S. 



Macrones peguensis. 



Depth of body 5| times in total length, length of head 

 3-| times. Head 1^ as long as broad, slightly granulate 

 above ; snout much depressed ; diameter of eye 8 times in 

 length of head, iuterorbital width 3 times ; maxillary barbel 

 reaching to middle of pectoral ; mandibular barbels subequal, 

 f length of head. Vomerine teeth in a crescentic uninter- 

 rupted band. No separate interneural shield on the nape. 

 Dorsal I 7 ; equally distant from end of snout and base of 

 caudal ; spine f length of head^ moderately strong, not 

 serrated ; adipose fin as long as dorsal, a little longer than 

 anal. Anal 12. Pectoral spine ^ length of head, strongly 

 serrated on the inner edge ; ventral reaching anus ; caudal 

 forked. Olive-grey above, white beneath ; a series of blackish 

 dotted lines cross the lateral line ; dorsal and caudal fins 

 dark, adipose fin blackish. 



Total length 20 millim. 



Closely allied to 2Iacrones planicepSj C. & V., but distin- 

 guished by the much shorter barbels. 



Two specimens from the Sittang River, near Toungooj 

 presented to the British Museum by Mr. E. W. Gates. 



