1572 THE VOYAGE OF H.M.S. CHALLENGER. 



Genus Simorhynchotus (Simorhynchus, 1 Claus, 1871). 



1871. Simorhynchus, Claus, Unters. tiber den Bau und die Verw. der Hyperiden. Nachrichten der 



K. Gott. Soc, p. 156. 

 1879. „ Claus, Die Gattungen und Arten der Platysceliden, pp. 32, 42. 



1886. ,, Gerstaecker, Bronn's Klassen und Ordnungen, Bd. v. Abth. ii. p. 486. 



1887. „ Bovallius, Systematical List of Amph. Hyper., Bihang till K. Svensk. 



Vetensk.-Akad. Handl., Bd. 11, No. 16, p. 34. 

 1887. „ Claus, Die Platysceliden, pp. 56, 65. 



For the shorter definition of this genus by Claus, see Note on Claus, 1879 (p. 493). 

 The following is based upon the fuller account which he also gives both in 1879 and 1887: — 



Upper Antennas with four-jointed flagellum, the first joint very large, the others narrow. 



Lower Antennae. — The first free joint (in the male) curved, much shorter than any of 

 the three following joints, which are long and liuear, the terminal joint short. 



Mandibles with three-jointed palp (in the male). 2 



Maxillee degraded. 



MaxilUpeds with small inner plate and large outer plates. 



First Gnathopods simple ; Second Gnathopods tending to a subchelate form. 



Third Perasop>ods longer than the Fourth, both pairs with expanded first joint. 



Fifth PersBopods with expanded first joint, the remaining joints present but feeble. 



Branchial Vesicles large, with accessory lateral compartments. 



Uropods of the Second and Third pairs having the inner ramus coalesced with the 

 peduncle, the outer movable, finger-like. 



Claus states that the ganglia in the ventral chain (which he figures) are very closely 

 set, with short longitudinal commissures ; that the hepatic tubes (which he also figures) 

 are broad, with secondary bulgings ; and that the heart (Kiickengefass) is very wide. 

 His description of the rodent-like head must no longer be included in the generic account, 

 since Bovallius describes a species, " Simorhynchus Lilljeborgi," with " Head rounded, not 

 rostrate." 



Simorhynchotus antennarius (Claus) (PI. CC). 



1871. Simorhynchus antennarius, Claus, Untersuch. iiber den Bau und die Verwandschaft der 



Hyperiden, Nachrichten K. Gott. Soc, p. 156. 



1879. „ „ Claus, Die Gattungen und Arten der Platysceliden, p. 43. 



1887. „ „ Bovallius, Systematical List of Amph. Hyper., Bihang till K. 



Svensk. Veteusk.-Akad. Handl., Bd. 11, No. 16, p. 34. 



1887. „ „ Claus, Die Platysceliden, p. 65, Taf. xvii. figs. 9-19. 



Head broad, produced a little in front, as if into a short blunt snout; the back 

 broad, the segments of the pereeon together not so long as the first three of the pleon ; the 



1 SimorhynehiLS, being preoccupied among birds (see Scudder, Nomenc. Zool., p. 292), has been changed into Simo- 

 rhynchotus. 



2 Claus says "Mandibular-palp short, basal joint only a little longer than the following joints," whereas in the 

 Challenger specimen the palp is relatively long, and its basal joint considerably longer than the second joint. 



