89 



weak that it breaks off) and naturally the claw loses the possibility of 

 retracting into the body of the segment. 



The formation of subchelae on pereopods III-V evidently assists in 

 better attachment of this crustacean to the host tissues than is inherent 

 in other Lanceola. 



Thus, in the series L. clausi — L sphaerica — L. chelifera a distinct 

 increase of specialization is observable in pereopods III-V and their mod- 

 ification from the simple to a prehensile type. An absolutely similar series 

 of changes in the appendages can also be traced in another group close 

 to the lanceolids, the family Microphasmidae. Unfortunately, all species 

 with transitionally structured pereopods are very rare and known from 

 lone specimens; hence it is not possible as yet to compare the above 

 changes in a larger series, which would enable identification of total and 

 individual variability. 



Distribution: Kuril-Kamchatka Trench. Evidently it inhabits only the 

 abyssopelagial as it has not been found even once at depths of less than 

 3,000 m; however, in the trench waters it has not been recorded deeper 

 than 6,000 m. 



2. Genus Scypholanceola Woltereck, 1905 



Woltereck, 1905; 414, 1927: 65; Bowman and Gruner, 1973: 22. 



Large crustaceans, up to 60 mm long. 



The integument is very thin and transparent. The structure is the 

 same as in the genus Lanceola, differing only in the unique structure of 

 the eyes, which are modified into reflector organs. The eyes resemble 

 a strip folded in half, the broadened ends of which lie in deep funnel- 

 shaped niches formed by the lateral walls of the head (Fig. 22). The 

 refractive elements and the eye pigment have disappeared while the 

 receptor elements are very highly developed. Eyes of similar structure 

 are known not only in Scypholanceola, but in some other deepwater 

 crustaceans of the orders Ostracoda, Copepoda, and others. According 

 to Woltereck (1909), they reflect the light falling on them form the lumi- 

 nous organs of other animals and flash it in the dark, attracting thereby 

 the prey or confusing the predators. 

 Type species: Scypholanceola vanhoejfeni Woltereck, 1905. 



Four species of this genus have been described: S. agassizi 

 Woltereck, S. aestiva (Stebbing) {=S. vanhoejfeni Woltereck), S. chuni 

 Woltereck, and S. richardi Chevreux. The difference between the last 

 three species is confined to a slightly different shape of the eye cups and 

 width of the eye strip. Howerver, Chevreux (1920) noted variability in 

 the shape of the eye cups when he described 5. richardi. Later, Woltereck 

 (1927) and Barnard (1932), after examining a large amount of material 

 from the Southern and Atlantic Oceans, concluded that the shape of the 



