90 



The body is rounded. The posterior or abdominal portion, con- 

 sisting of a membranous sac marked with delicate lines, and allowing 

 the ccecal sacs of the intestine to be seen through it: fig. 1. The 

 anal orifice is about the middle of the abdomen inferiorly : fig. 2. 

 The anterior part of the body, on the back, is covered with a horny 

 shield, which partially covers the oral apparatus or head, and presents 

 a contraction opposite the junction of this apparatus with the trunk: 

 fig. 1. The oral apparatus or head consists of two lateral palpi with 

 the maxillae to which they are attached, of a sternal labium and two 

 mandibles. 



The palpi (c, fig. 1, 2, a, fig. 5, 6) are thick and hollow, and beset 

 with long hairs or spines, and have inferiorly at their extremities a 

 papillary process set round with long spines, which is apparently re- 

 tractile, as seen in fig. 8, or extended in fig. 7. These organs are not 

 perforated. The maxillae are seen at c, fig. 6. The mandibles {b,b, 

 fig. 7) consist of a delicate, transparent, scaly sheath, surrounding a 

 tubular apparatus which contains the organs by which the tick obtains 

 its nutriment. These organs are more fully represented in fig. 9, and 

 consist of two blades, one for cutting and one resembling a saw, be- 

 sides a hook, and a small tube with a projecting lip a little below its 

 extremity, and evidently for the purpose of suction. This smaller 

 tube (a, fig. 9) is articulated just within the orifice of the larger one, 

 and is apparently furnished with muscles, by which it can be moved 

 in any direction, or retracted. In the usual state of the animal, this 

 collection of instruments lies concealed within the larger tube, which 

 is again enclosed within the transparent sheath, and the two mandi- 

 bles are closely embraced by the palpi, and supported below on the 

 sternal labium ; but by moderate pressure between glass, the appara- 

 tus can be made to expand, as in fig. 7, 8, where the extremity of the 

 large central tube of the mandible is extruded from its sheath, and 

 opens on its external side, to allow of the projection of the enclosed 

 instruments. The inner portion of the tube forms a sort of hood or 

 lid, and is articulated so as to perform that function. 



The sternal labium is represented at a (fig. 8), and is remarkable by 

 its curious scales. 



The intestinal canal appears to be continuous with the tubes of 

 the mandibles, which are evidently prolonged into the trunk, and it 

 presents numerous large cceca. From the immature condition of the 

 present specimens, no reproductive organs are to be distinguished : 

 nor can I perceive any circulation, nor any tracheae. 



The legs consist of seven joints, and are of nearly equal size and 



