NO. 10 I'EEUINU ORGANS OF AKACH N JIM — SNOLKiKASS 3I 



l)rey with the pccHiwIp chelae, and to further hiceratc it with the 

 chehccrae. The exuding juices, caught in the open trough of the 

 pedipalp coxae, must be sucked in by the action of the pharynx. N'o 

 evidence of cxtraoral (lif;estif)n by these arachnids has l>een observed. 



V. THE RICINUI.ia 



1 he Miiall and rare araclinids of this order inckide IJ kiKJwn hving 

 species from Africa, Central America, and South America, and ex- 

 tinct Palaeozoic species from Europe and North America. The living 

 forms, according to Ewing (1929), belong to two genera; one, 

 Ricinoides lowing (formerly Cryptostemma) is represented by six 

 species in Africa, the other, Crypt ocellus West wood, includes six 

 .\merican species. The structure of the feeding organs of the Ricinulei 

 is known only from the work of Hansen and Sorensen (1904), the 

 scarcity of specimens in collections making them too valuable for 

 anatomical purposes. 



A distinctive feature of the Ricinulei is the presence of a large 

 hoodlike lobe, the cucullus, movably hinged to the anterior margin of 

 the carapace, which ordinarily (tig. 10 P., Luc) conceals the chclicerae 

 and the mouth region below it (A). The under surface of the cucullus 

 bears a median ridge separating lateral concavities that fit over the 

 chelicerae, whicli structure, as noted by Hansen and Sorensen (1904). 

 suggests that the ricinuleid cucullus represents the anterior part of 

 the carapace of the Thelyphonidae that overhangs and conceals the 

 chelicerae. The chelicerae of the Ricinulei (D) arc two-segmented 

 as in the Pedipalpida. The small, chelate pedipalps (A, 15, Pdp) 

 have a ventral position, and their coxae are completely united to form 

 a trough below the mouth. The pedipalp segmentation (E) is simple 

 compared with that of the legs (B), there being two trochanteral 

 segments {iTr, 2Tr) as in the legs, but the tibia is a long slender 

 segment {Tb), and the tarsus {Tar) forms the small movable finger 

 of the chela. In the legs (C) a patella intervenes between the femur 

 and the short tibia, while the tarsus is divided into a long basal sub- 

 segment and five short distal subsegments. 



The mouth region of the Ricinulei (fig. 10 C) resembles that of 

 the Thelyphonidae (fig. 9B) in that the floor of the prcoral cavity 

 (PrC) is formed by the united pedipalp coxae. In the ricinuleid. 

 however, there are no free coxal processes since the coxae arc here 

 entirely united in a broad, troughlike under lip (fig. 10 C, list), 

 which would appear to l)e quite comparable to the hypostome of 

 .\carina (fig. 26 :\, B, Hst). Projecting over the proximal part of the 



