32 



CARL BOVALLIUS, THE OXYCEPHALIDS. 



This is the same " form of prehensile organ 

 which exists in the third and fourth and also in 

 the fifth pair of peraeopoda in Euthemisto and Para- 

 tkemisto. Moreover the folding hand is common 

 in the Amplnpoda Gammaridea, in the first three 

 pairs of peraeopoda in some families of Isopoda, and 

 is probably most strongly developed in the first pair 

 of Squ'dla and other Stomatopods. 



The next step in the development of these 

 organs is represented in many genera, as for in- 



8ta " ce in the e t C nd P1)ir hl SimorhynchotuB, the 

 first pair in Streetsia (fig. 52), the first pair in 



Dorycephalus, the first and second pairs in Tullbergella (fig. 51), 



and in others, that is to say: 



2. The subcheliform hand, (fig. 51 53) in which the carpus is broadly 



dilated backwards, but not produced downwards, 

 or only very little produced, so that the meta- 

 carpus impinges against the under margin of 

 the carpus, the dactylus here coming in contact 

 with the hind margin of the carpus. When the. 

 \ J hind margin of the metacarpus is in contact 

 with the under margin of the carpus, the meta- 



Fig. 51. The first pair of carpus is at a right angle with the axis of the leg, 

 la cuspidata. the leg being supposed to hang straight down. 



Fig. 52. The first pair of 

 Streetsia Steentrupi. 



Fig. 53. The first pair of 

 Cranocephalus Goesi. 



The next form, the most developed prehensile organ, is best re- 

 presented in the second pair of peraeopoda in the genus Oxycephalus 

 (fig. 54), but is also met with in the first pair in the same genus, in the 

 second pair in Streetsia (fig. 55), and in others; that is to say: 



