Fig. 4. — Diagram of a transverse section of the hinder part of the prosoma of 

 the Italian scorpion (Euscorpius Italic us, Roess.) passing through 

 the pentagonal metasternal plate z, and showing the relations of the 

 entosternite T, its sub-neural arch ?7, the coxal glands (of the right side) 

 S, and the gastric ca;ca o. It is important to note that the spaces left 

 between various organs are in some cases natural blood-sinuses, in other 

 cases they are due to shrinking in the process of preparing the section. 

 It is difficult to determine which are natural and which shrinkage spaces, 

 but for the present purpose this is immaterial. The following is a com- 

 plete list of reference letters. — a. Tergo-plastral muscle (from tergal 

 tegumentary sclerite to the entosternite or "plastron"), b. Pleuro- 

 plastral muscle, c. Sterno-plastral muscle, d. Sterno-hyponeural muscle. 

 e. Longitudinal pectoral muscle in transverse section. /. Muscle in the 

 coxa of the sixth prosomatic limb in transverse section, g, g, g. Muscles 

 in the coxa of the Qftli prosomatic limb. h. Dorsal longitudinal muscle 

 in transverse section, i. Part of a dorso-ventral muscle, cut parallel with 

 its fibres, k. Similar to h. I. Similar to i. m. Similar to h. n. Similar 

 to i. 0. Caica of the gastric gland in section, p. The axial portion of 

 the alimentary canal, q. The anterior aorta. ;•. A mass of connective 

 tissue investing the two nerve-cords (riglit and left) and the supra- 

 medullary artery (median). S. The right coxal gland. T. The body of 

 the entosternite. U. The subneural arch of the entosternite (the section 

 is taken at a plane in front of the connection of these two parts of the 

 entosternite). w. Tissue connecting the subneural arch of the ento- 

 sternite with the tegumentary metasternal (pentagonal) plate z. x. Chi- 

 tinous sclerite of the tergum. _y. Soft tegumentary membrane forming 

 the sides of the body and connecting the sclerites of the dorsal and 

 ventral surfaces, z. The pentagonal metasternite in section : immediately 

 adjacent to it is the coxa of the sixth prosomatic limb containing a 

 muscle marked /, beyond this again is the coxa of the fifth prosomatic 

 limb, with muscles marked g. The sclerite of the coxa of the fifth pro- 

 somatic limb on the left side is marked aij. 



