=Internal Structure.=—The anatomy of the Pedipalpi has been very inadequately studied. Disconnected notes on various points of structure have been published by various morphologists, but no complete investigation has yet been made of the internal organs. This is largely due to the difficulty of obtaining material, and the bad state of preservation of the internal parts of such specimens as have been available for dissection. The following points have been made out in the anatomy of _Thelyphonus_.[250] The alimentary canal commences after the mouth with a pharynx which, though not dilated, is furnished with sucking muscles. It then narrows into an oesophagus which passes through the nerve-mass, and afterwards dilates to form the mid-gut, which immediately gives off two large lateral diverticula which extend backwards, each having five lobes. There are also two median diverticula which proceed from the ventral surface and pass through the endosternite. The abdominal portion of the canal is entirely concealed by the great “liver” mass which communicates with it by four paired ducts in the anterior part of the abdomen. Behind the fourth abdominal segment the gut is narrow till it expands in the seventh segment into an hour-glass-shaped stercoral pocket which, according to Laurie, is a portion of the mesenteron. The excretory organs are the Malpighian tubes and the coxal glands. The former are generally described as entering the anterior portion of the stercoral pocket, but according to Laurie they pass along its ventral surface, attached to it by connective tissue, and really enter at the posterior end. The coxal glands are well developed, and lie beneath the endosternite, opening near the first coxae. The nervous system is much concentrated and of the usual Arachnid type. The median abdominal nerve has a ganglion towards its extremity, supplying, according to Bernard,[251] the muscles which move the tail. The heart is extremely long, and varies little in width. It has nine pairs of ostia[252]—two in the thorax and seven in the abdomen. The generative glands are paired, and in the male there are large seminal vesicles. In the most ventral portion of the abdominal cavity lies a remarkable asymmetrically-situated gland, the “stink-gland.” It consists of a number of secretory tubules communicating with two elongated sacs, one of which lies beneath the nerve-cord, and therefore medially, while the other lies far to the left. Their ducts proceed to the anus or its vicinity.