186/.] MR.W. H. FLOWER ON HYOMOSCHUS AQUATICUS. 9.55 



of the Royal College of Surgeons, of the body of a young female 

 Hi/omoschus aquaticus, which died in June last, in the Gardens of 

 this Society. 



The animal was not quite full-grown, the milk-teeth being still in 

 place, with the first and second permanent molars. The various 

 organs were compared during the examination with those of a speci- 

 men of Trac/ulus javanicus of the same age and sex. 



The tongue is 3| inches long, and -f-^J inch in average breadth, 

 rather fleshy, with sides nearly parallel, flat above, and obtusely 

 pointed at the tip. Along the anterior half is a median linear de- 

 pression. Numerous white, flat- topped, circular, circumvallate pa- 

 pillae are scattered irregularly over all parts of the surface, those at 

 the hinder part being rather larger than the others. Quite at the 

 root is a group of large, closely set, sharp-pointed, conical papillae. 

 These seem to be of the same class as the minute pointed papillae 

 with which the entire surface of the organ is beset developed to an 

 unusual degree. On each side of the upper surface, near the poste- 

 rior end, is a long, narrow, and deep groove, -f^ inch in length, placed 

 obliquely, so that the posterior end inclines towards the middle line. 

 The edges of this groove are thickened, white, and free from papillae ; 

 and within it is a linear papillary elevation, with a faintly notched 

 free border, projecting slightly above the level of the surrounding 

 parts. This, which appears to be a modification of a circumvallate 

 papilla, occurs also in Tragulus jaoanicus. 



The larynx presents a peculiarity in its construction which is not 

 met with in Tragulus, or, as I'ar as my knowledge extends, in any 

 other ruminant. The whole organ is remarkably large and promi- 

 nent — a circumstance mainly caused by the extraordinary develop- 

 ment of the thyroid cartilage (a, fig. 1, p. 956). This is formed as 

 usual, by two broad lateral plates united at a very salient angle in front. 

 The entire length of the cartilage in the middle line is ly^jj inch. 

 Its upper border has three distinct triangular projections — one in the 

 middle line, broader and shorter than the others, and one on each 

 side, attached to the inferior cornua of the hyoid. The lateral mar- 

 gins, -f-fj inch in length, are gently and regularly excavated, and ter- 

 minate below in a short, pointed triangular process for articulation 

 with the cricoid cartilage. Below this point the thyroid is continued 

 downward ; and instead of being open below as usual, its sides are 

 united across the middle line, so as to form a considerable, rounded, 

 compressed pouch, placed in front of the commencement of the 

 trachea. 



In Tragulus javanicus the whole vertical depth of the thyroid is 

 but -f^ inch, and it is widely open below, and presents no anterior 

 prominence. In the larynx of the Sheep there is a well-marked pro- 

 jection of the anterior edge of the thyroid rather below the middle, 

 but off"ering only a slight indication of that which is so remarkably 

 developed in Hi/omoschus. 



The cricoid cartilage (6) forms a strong shield behind, -J^ inch 

 in length, and the same in breadth. Its thickened upper margin is 

 hollowed in the middle line, and on each side presents a large oblique 



