62 



1888 off the south-west coast, but the specimens were re- 

 corded under the name of U. rubrovittatus (see p. 58). 

 The Helga has taken this species at three stations. 

 Helga. 



S. R. 493.-8 IX '07. 51° 58' N., 12° 25' W., 533-570 fms. 



Trawl. — One, 21 mm. 

 S. R. 494.-8 IX '07. 51° 59' N., 12° 32' W., 550-570 fms. 



Trawl. — One, 27 mm. 

 S. R. 500.— 11 IX '07. 50° 52' N., 11° 26' W., 625-666 fms. 



Trawl. — One, 25 mm. 



Vertical Distribution. — The species is most commonly found 

 in depths ranging from 400 fathoms to 650 fathoms, but it 

 has been found in 318 fathoms and in 808 fathoms. 



Genus Gastroptychus, CauUery. 



Ptychogaster , Milne-Edwards, 1880. Ptychogaster, Henderson, 

 1888. Chirostylus, Ortmann, 1891-94. Gastroptychus, Caullery, 

 1896. Ptychogaster, Milne-Edwards and Bouvier, 1900. Ptycho- 

 gaster, Alcock, 1901. 



Gastroptychus formosus (Milne-Edwards). 



PL IX, figs. 2-8, PL X, fig. 1. 



Ptychogaster formosus, Filhol, 1886. 



Ptychogaster formosus, Perrier, 1886. 



Ptychogaster formosus, Milne-Edwards and Bouvier, 



1894 (b). 

 Gastroptychus formosus, Caullery, 1896. 

 Ptychogaster formosus, Milne-Edwards and Bouvier, 1900 



The carapace is much narrower in front than behind ; its 

 broadest part is a short distance behind the cervical groove. 

 In front there is a narrow spiniform upturned rostrum, about 

 twice the length of the eyestalks ; its margins are entire. The 

 gastric region of the carapace is inflated and sharply marked 

 o:ff from the surrounding parts. The carapace is furnished with 

 a large number of spines. At each side of the base of the rostrum, 

 above the eyes, there is a large spine ; behind these, and much 

 wider apart, is another pair of large spines ; near the posterior 

 edge of the gastric area there are two spines opposite the supra- 

 orbital ones in front ; on the centre of the gastric area there is 

 a large unpaired spine, so that on this part of the carapace 

 there is a ring of six large spines enclosing a single median one. 

 Just behind the cervical groove there are two median spines, 

 and farther back a similar pair, while a third pair is situated 

 on the posterior margin of the carapace. On the hepatic region 

 there are two large spines on each side, and between these and 

 nearer the median line is another spine. There are rows of 

 smaller spines on the branchial regions, running parallel to the 

 lateral margin of the carapace. Between the spines the surface 

 of the carapace is perfectly smooth. The cervical groove is 



