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



much more developed condition than the right (figs. 2 and 3). In the latter specimen 

 the left ins deferens (vd) is much wider than the right (vd'), and provided in its 

 interior with low, circular, closely-set septa (fig. 4), of which only faint traces can be 

 seen in the right duct. They are, however, limited to the lower 3 or 4 inches of 

 the duct. The left vas deferens opens into the urinary bladder (fig. 3, u), if a bottle- 

 shaped dilatation which terminates externally in a single small conical papilla {ug') may 

 be so called. The right vas deferens opens by a slit at the side of the papilla directly 

 into the cloaca (figs. 2 and 3, ug). There is also in this specimen only one iwrus 

 abdominalis in the median line (or very slightly to the left of it) immediately behind 

 the cloaca (figs. 2 and 3, po). 



The conus arteriosus (figs. 7 and 8) is of considerable length, slightly bent towards the 

 right, and of nearly the same diameter throughout. No special valve separates it from the 

 ventricle. I find the valves much more regularly arranged than would appear from the 

 figure given by Garman. They form three longitudinal and six transverse rows (fig. 8). 

 The largest are those of the distal transverse row, placed close to the end of the conus, and 

 somewhat more distant from the next row than the five other rows are from each other. 

 The next largest valves are those of the proximal row, those of the second and third 

 being smaller, and those of the fourth still smaller, with only partially free anterior margins ; 

 the valves of the fifth row are quite rudimentary, and two of them merely indicated as 

 raised papillae, which are confluent with those of the fourth row. Finally, a fourth 

 intermediate longitudinal series is indicated by two minute valves, belonging to the first 

 and second transverse rows. The larger valves are provided with tendinous chordae. 



Family S p i n a c i d ^. 



Spinax, M. and H. 

 Spinax spinax, L. 



The common European species is reported by Strom ' to be common in Throndjhem 

 Fjord, at a depth of from 70 to 300 fathoms. 



Spinax granxdosus. 



Spinax gramdoms, Giinth., Keport on the Shore Fishes, Zool. Chall. Exp., part vi. p. 19, 

 pi. ii. 2, fig. C. 



Ilahitat. — South-western coast of South America, Station 305a; depth, 125 



fathoms. One specimen, 10^ inches long. 



Centrophorus, M. and H. 

 The two Japanese species here described live at about the same depth as the Atlantic 

 species, all of which have been hitherto found in the Mediterranean, off Madeira, and on 



» Norsk. Vid. SeUk. Skrift., 1884, p. 44. 



