58 ZOOLOGY. 
upon the extend of the first segment, the third being considerably developed upon its upper 
region, which is prominently convex. The remaining portion of the tail is very much reduced, 
tapering posteriorly, bent downwards and forwards under the body. The lateral and free 
expansions of the anterior three caudal segments are rounded off; that of the second segment 
is the largest, subcircular in shape, external, and covering partly the expansions of the first 
and the third segments. In the fourth and fifth segments that expansion is subtriangular, 
posteriorly acute. The sixth ring has no such lamellar expansions, but is provided upon its 
posterior and inferior angle with a slight ridge, at the inner margin of which a row of sete is 
observed similar to that which exists upon the external margin of the lamelle of the other 
segments. The central caudal appendage, subconical in shape, elongated and tapering, is con- 
vex above, concave beneath, and terminated by three pairs of spines; a very minute external 
pair, and two median, the upper one very slender, and two thirds the length of the lower pair, 
which is the most conspicuous. Along the upper and convex surface there are three pairs of 
rather short, stoutish, though small spines. On each side of this central appendage, and 
inserted in a concavity of the lateral and posterior edge of the sixth segment, with one spiny pro- 
cessus above and below, is another appendage composed of a short basal piece, upon which are 
inserted two moveable very thin lanceolated lamelle, provided upon their edges with well devel- 
oped setee disposed upon one close series. The inner lamella is made of a solitary piece; the 
external one is composed of two pieces, the undulated and transversal articulation of which 
may be seen across the posterior third of said lamella, exteriorly marked by two small spines 
belonging to the largest piece. 
The caudal or oviferic legs, five in number (one pair for each anterior five caudal segments), 
are of moderate development, the second and third pair being the largest. The posterior four, 
pairs are similarly constructed. They consist of a flattened article, terminated by two narrow, 
elongated, thin blades, margined with sete. The anterior pair is distinguished from the others 
in the structure of the terminal pieces, the inner of which is short and rather broad, and de- 
prived of setze upon its edge, whilst the outer one is similar to those of the other legs, being, 
however, considerably smaller. 
The surface of the carapax is almost entirely smooth; a minute, prickly granulation becomes 
visible under a magnifying glass and to the touch also. This granulation is more apparent 
upon the locomotory and other appendages than elsewhere. The upper margin of the large claw 
is provided with an elongated tuft of setee extending from the anterior portion of the hand 
(so called) along the convexity of the finger to near its apex. An elongated cushion of short 
sete may also be observed along the convexity of the finger to near its apex. An elongated 
cushion of short setee may also be observed along the inner surface of the third, fourth, and the 
base of the fifth article of the jaw-legs. Scattered bristles or sete exist along the inner surface 
of most of the articles constituting the legs, and principally upon the mandibles. 
The ground-color is yellowish; the sides of the cephalothorax and tail are variegated with 
irregularly meandric, fuliginous red macule. The appendages are annulated with purplish 
red. The third caudal ring is purplish upon its convexity, exhibiting two parallel light vitte 
along the upper surface of the anterior three rings, uniting at an acute angle upon the poste- 
rior portion of the third ring. The caudal legs are spotted with fuliginous red, 
The specimens were caught in Caldera bay. 
