338 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



owing to their paucity in that individual, but I have found them on re-exam- 

 ination. They were largest and most abundant in a large female, and appeared 

 to be absent in only three specimens. Each pit has the form of a sack of 

 spherical or ovoid shape (some are flattened parallel to the surface of the cuti- 

 cle), with an exterior opening on the surface of the cuticle ; the length of 

 these sacks varies from about one-fourth to two-fifths the diameter of the 

 cuticle. On section it would appear that almost all of them lie between 

 areoles, sunk into the fibrous cuticle, though on surface view they frequentiy 

 seem to lie on the summits of areoles. The outline of each pit is rounded 

 and sharply demarcated, though no special limiting membrane appears to be 

 present. In each lie two (rarely three) refractive spines, which are usually 

 situated vertical to the surface of the cuticle, but in some cases parallel to it. 

 Each spine is somewhat rod-shaped, thickest basally, the base obtusely 

 rounded and usually in close contact with the wall of the pit. At its distal 

 end each spine has a short, pointed process which projects out of the narrow 

 opening of the pit ; the longitudinal axis of this pointed portion does not 

 always coincide with that of the basal portion. Thus these spines are some- 

 what similar in form to the central stilets (with their bases) of the Metane- 

 mertean proboscis. 



Color. — The males vary from a light yellowish, through rufous or chocolate 

 or olive-brown, to a nearly pitch black color, smaller individuals being usually 

 but not always lighter than larger ones. In most of them the anterior portion 

 of the body is lighter than the posterior ; the head is lightest in color, very 

 frequently yellowish white, while the rest of the body is chocolate-brown. 

 Just behind the light head portion is usually a more or less pronounced dark 

 neck ring, which is seldom wholly absent. The females average much 

 lighter in color than the males, and are usually a yellowish or yellowish 

 brown color ; a few are a dark olive-brown, but none are black. In them, 

 too, there is usually a darker neck ring, and often a brownish area around 

 the cloacal aperture. In both sexes the mouth aperture is usually marked 

 by a small black spot, easily seen with a hand lens : thus of the 154 individ- 

 uals collected on the same day at the same locality (coll. Stanford University), 

 96 males showed this spot, 15 males were without it, and in 2 males the 

 whole head was black ; and all the 42 females showed the spot. The black 

 mouth spot would thus appear to be pretty constant (though it was absent 

 in the type specimens of this species). 



Dimensions. — Largest male, 460 mm.; largest female, 420 mm. 



Comparison. — C. gordioides Montg. becomes a synonym 

 of this species. This species differs from C. bedriagcB and 

 C. -pardalis Camer., to which the configuration of its cuti- 

 cle appears to be otherwise quite similar, in the presence 

 of the remarkable cuticular pits, the structure of which, 

 however, can only be determined by sections. Such pits 

 have never heretofore been described: but clear, rounded 

 cavities situated just below tubercles or aeroles of the cuticle 



