1496 THE VOYAGE OF H.M.S. CHALLENGER. 



Genus Parascelus, Claus, 1879. 



1879. Parascelus, 1 Claus, Die Gattungen und Arten der Platysceliden, pp. 17, 18. 



1885. ,, Carus, Prodromus Faunae Mediterranese, pars ii. p. 425. 



1886. „ Gerstaecker, Bronn's Klassen und Ordnungen, Bd. v. Abth. ii. p. 483. 



1887. „ Bovallius, Systematical List of Ainph. Hyper., Bihang till K. Svensk. Vetensk.- 



Akad. Handl., Bd. 11, No. 16, p. 43. 

 1887. „ Claus, Die Parasceliden, pp. 43, 45. 



For the shorter definition of this genus by Claus in 1879, see Note on Claus, 1879 

 (p. 492). In the fuller account he says : — 



" Body moderately broad and rounded, yet with flattened ventral surface, as in 

 Tanyscelus. Upper lip and maxillipeds projecting beak-like. The former with tongue- 

 shaped projecting epipharynx. Mandibles narrow, outdrawn almost stiletto-like. Upper 

 antenna? as in Tanyscelus. Limbs of the perseon very slender, with very long first joint. 

 TJie gnathopods simple (enden klauenformig). The wrist in the gnathopods with small 

 tubercular prominence a suggestion as it were of a chela-forming process. Laminar 

 first joint of the third perseopods compactly ovoid. Laminar first joint of the fourth 

 perseopods elongate, distally narrowed, without pocket-like groove. Fifth perseopods 

 completely developed. The rami of the uropods are narrow fin-laniinse (Flossenblatter), 

 the inner of the second pair being the largest." 



Gerstaecker in the definition of this genus includes two other characters, namely, that 

 the head has summit-e3 r es and lateral-eyes combined, and that there are two gland-cells 

 in the fourth joint of the first and second peraeopods. 



Dana's account of Thyropus does not include any mention of the pocket-like groove 

 of the fourth perseopods as either present or absent, but the very elongated termination 

 of the first joint in those limbs, with the remaining joints not reaching to its apex, 

 confirms the view that Thyropus coincides rather with Claus' Tanyscelus than with his 

 Parascelus. In Dana's TJiyropus the fifth perseopods have only two or three joints, but 

 it is evident that these limbs vary in the number of joints within the genus, if not 

 within the species or in the individual. 



Parascelus zebu, n. sp. (PI. CLXXXV.). 



Head deeper than long, the flattened front a little produced at the lower end over 

 the insertion of the upper antennae ; the second segment of the perseon the shortest ; 

 first three segments of the pleon postero-laterally almost squared. 



Eyes as in Tliyrop>us. 



Upper Antennas. — In the male, first joint of the peduncle widening distally, the 

 two following joints short, incompletely developed ; the first joint of the flagellum 



1 Given as Parascellus in the Zuol. Jahresb. (see Scuddet's Nomenclator Zool., p. 248). 



