VISCERAL ANATOMY. 43 



These appear to Ijc similar to those of S. cubanus as figured by Peters ('64, Plate 

 2, fig. 11), and are well ossified. The thyroid is the largest, 13 mm. in greatest 

 length. It is slightly more tlian half a complete ring and has at the anterior 

 dorsal margin on each side a process for the articulation with the tips of the 

 thyrohyals. Posteriorly, the dorsal margin is similarly produced to form 

 processes articulating with the posterolateral margin of the cricoid. A l(jw 

 ridge arises al^out midway of the straight dorsal Ixjrder and curves ventrally to 

 the ])ostcrior edge. Above it on eacli side is a minute foramen at the tlorsal 

 edge of the bone. On the left side in our specimen there is in addition a mi- 

 nute foramen about 2 nnn. anterior to the first. The tliyrohyal of each side 

 has fused ventrally with the basihyal so that the three bones thus form a half 

 ring, bowed back at first, then forward at the ventral side. The cei'atohyals 

 are appressed against the ventro-lateral margin of this ring. They are rather 

 thick and about 4 mm. in dorso-ventral length. Their dorsal border, and the 

 edge of the thyrohyal adjacent, articulate on each side with the ejjihyal, a 

 broad Imt laterally flattened lione, that iirojects anteriorly from this articuhi- 

 tion. This in turn joins witli the stylohyal, which is al)out 2 mm. longer, and 

 much more rounded and slender. It joins the skull by a very sliort bony proc- 

 ess that projects at nearly right angles from its proximal end. This process 

 may represent a fused tymjianohyal. The cricoid at its anterior end is 

 clasi)ed by the converging posterior processes of the thyroitl and is a complete 

 bony ring, with a poste ro-dorsal extension. The vocal cords are attached by 

 cartilage, one at each side from the anterior apex of this ring to its mid-ventral 

 line, and pass forward as a delicate strand to a median attachment just back of 

 the anterior edge of the thyroid. The first tracheal ring is the broadest and fits 

 into the posterior end of the cricoid, to wliich it is bound l:)y muscle fibers. 

 Peters states that in Solenodon cubanus the first nine tracheal rings are complete 

 and that there are 21 in all. In S. paradoxus the number is slightly more, 22 

 to 29, and all are incomplete dorsally. The closest approximation is anteriorly 

 where the two ends of the partial rings are about 2 mm. apart. 



VISCERAL ANATOMY. 



Digestive system. — The surface of the palate is marked by transverse folds 

 whose number seems commonly to be eight, omitting the ridge bounding the 

 posterior end. Tiie first is a short transverse ridge between the third incisors; 

 the second is larger and passes across at about the middle of the canines; the 



