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Show (i MR. E. J. SIDEBOTHAM O N T H E [Jan. 20, diverticula of the annular stomach; e, annular stomach ; S, suctorial organ ; m, nerves of the fourth pair of ambulatory legs ; n, abdominal nerve. ,_ , . Fig. 2. Diagram of the left part of the cephalothorax of Mygale ccementarta, Latr. to show the horizontal projection of the coxal gland ; X65. a, The coxal gland. 1, Cheliferae. 2, Chela?. 3-6, The four last pairs of cephalothoracic appendages. A. Abdomen. 3. The same specimen as in fig. 4. To the left hand the upper prolongations (p) of the entosternite show only the coxal lobes (a) of the gland ; on the right, the same prolongations and the lateral diverticula (d) of the annular stomach hide all but very small parts {a) of the gland. 8. Suctorial organ. 4. The left coxal gland and the entosternite of Mygale, sp., from South America, in situ, dorsal view; X2£. The superior prolongations of the entosternite have been removed along the line ii, to show, on the right side, the coxal gland in its entirety, and on the right side the lower plate of the entosternite, which on' the left is hidden by the gland, a, The coxal gland ; b, its coxal lobes ; c, its internal projections. E, The entosternite. 3-6, The coxa; of the ambulatory legs. A.B, Line showing the direction of the section in fig. 1. 2. On the Myology of the Water-Opossum. By E. J. SIDEBOTHAM, B.A., late Assistant Demonstrator of Anatomy, Cambridge. [Received November 20, 1884.] Through the great kindness of Professor Macalister I have had the opportunity of making a careful dissection of the muscular system of the Water-Opossum {Ghironectes variegatus). The specimen, which was that of a young male, was a spirit one, and the muscles were in a very good state of preservation. When I received it the skin and abdominal viscera had been removed, some of the superficial muscles were considerably damaged, and most of the terminal phalanges had disappeared. It had the following dimensions :-- centim. Extreme length 59 Length of tail (measured from sacro-iliac synchondrosis). . 37*4 Length of humerus 41 Length of femur 5 Length of tarsus (terminal phalanx having disappeared) .. 6*1 Through the courtesy of Professor Flower I was enabled to measure the five specimens of this animal in the National Collection at South Kensington. The four stuffed specimens varied in length from 68*7 cm. to 4L5 cm., the tarsus varying from 6-7 cm. to 3*9 cm. The skin of the remaining specimen measured 67'6 cm. in length, the femur 5*6 cm., the humerus 4 / cm., and the tarsus 5'9 cm. Muscles of Anterior Extremity. Rhomboideus.-Indivisible, arising from inner two thirds of occipital crest, from spines of cervical and first five dorsal vertebrae |