44 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 10 



supported on an epistomal plate between the pedipalp coxae. An 

 under lip, when present, is formed by the projecting sternum of 

 the first-leg segment. 



The mouth parts of the Cyphophthalmi, of which a general com- 

 parative account is given by Hansen and Sorensen (1904), are of 

 more simple structure than those of the other two suborders of the 

 Phalangida. The following description of the parts in Holosiro 

 acaroides Ewing is made from specimens furnished by Dr. I. M. 

 Newell of the University of Oregon. 



The chelicerae of Holosiro (fig. 15 C) are relatively long, and are 

 three-segmented, with the movable finger of the chela articulated 

 laterally on the second segment. The pedipalp telopodites (I, Pdp) 

 are slender, smaller than the legs, but the coxae {11 Cx) are large, and 

 each bears a large endite (IIEndt) projecting ventrally and mesally. 

 On removing the appendage, the endite is seen to be a solid extension 

 from the inner face of the coxa (A, B, Endt) ending with a soft 

 ventral lobe. The convex outer surface of the lobe (A) is clothed 

 with small setae, the flat or slightly concave inner surface (B) is 

 finely and closely striated. The two apposed pedipalp endites present 

 ventrally rounded padlike surfaces (I, IIEndt) separated by a narrow 

 cleft that leads up to the mouth. Though coxal muscles of the pedi- 

 palps are attached on the endites, the latter are so firmly fixed on the 

 coxae that they have no independent movement. 



The mouth of the Cyphophthalmids is entirely concealed beneath 

 the bases of the chelicerae and between the pedipalp endites. Above 

 the mouth is a U-shaped epistomal plate (fig. 15 D, Epst) supporting 

 the labrum (Lm). In the specimens of Holosiro examined, the labrum 

 was broken in dissection, but Hansen and Sorensen (1904) describe 

 the organ in other cyphophthalmids as a thin, laterally compressed 

 plate projecting downward and forward from the "clypeus" between 

 the pedipalp coxae. The "clypeus" of these writers is the epistome. 



The ventral surface of the prosoma of Holosiro (fig. 15 I) is 

 occupied entirely by the large coxal segments of the legs, the long 

 axes of which radiate on each side from a point in front of the genital 

 opening. The coxae of the first legs (IIIC.v) are thus turned forward 

 so that they embrace the pedipalp coxae (IICx). Each first-leg coxa 

 is traversed anteroposteriorly across its middle by a strong ridge (cxr) 

 that runs out in a small point on the anterior coxal margin, and forms 

 the lower edge of a broad, slightly concave surface on the inner side 

 of the coxa (E, F, I), which bears at its mesal end a soft, rounded, 

 lobular endite (Endt) with a small, hairy papilla behind the pedipalp 

 endite. Between the two opposed mesal surfaces of the first-leg coxae 



