STEEXA HIRUXDO, COMMON TEEN. 681: 



B.^S. hirundo ex AmericS. 



Locality. 



Labrador ' 11.00* 



Massachusetts j 10.40 



CapeM:iv, X. J ! 10.60 



Hmlsou's" Bay ' 10. 40 



Utah 1 ! 10.50 



* Inches and hundredths. 



AnatomimJ characters. — The mouth is only moderately large, it being exceedingly 

 narrow anteriorly, and only widening toward the fauces, where, however, the diverg- 

 ence of the tomia gives it considerable breadth. The palate is concave aotero-posteri- 

 orly. but is nearly flat laterally. It is soft and vascular only for about two-thirds its 

 length, the anterior third being corneons, and being merely a deep, narrow, longitud- 

 inal depression for the reception of the closely-approximated rami of the inferior max- 

 illa. This single depression bifurcates about three-fourths of au inch from the Tip. and 

 for the rest c f the extent of the palate there is a deep depres-ion on each siik, just 

 within the snpirior tomia and zygoma, for the reception of the devarici'tiug rami of 

 the inferior maxilla. On the median line there is a slightly marked ridge, very short, 

 however, and quickly bifni'catlng to form the fissure of the posterior mues. The edgee 

 of this median elevation, on which the unres oi>eu. are beset \\'ith a single row of small 

 obtuse papill*. On either side of the median line is a longitudinal su'cns, which sei>- 

 arates a lateral longitudinal ridge, which is beset posteriorly with more prominent and 

 acutely-pointed papillse. These various ridges and sulci all terminate in papillated 

 extremities. Beyond them the palate is quite smooth, somewhat vaulted, still divided 

 in two by the backward continuance of the nasal fissure. This vaulted portion is 

 1h iinded posteriorly by two obliquely-placed curved rows of small acute papillfe, con- 

 taining between them an oval foramen, the opening of the Eustachian tube. 



The floor of the month has the form of an elongated, narrow isosceles triangle with 

 concave sides. The i-.;mi are so closely approximated ifrom the commencement of the 

 symphysis as merely to leave room for the reception of the tongue. The floor of the 

 mouth, though dilatable, is not so much so as in the other subfamilies, and the soft 

 membranes terminate fully an inch from the tip. The tongue arises about oppo- 

 site the termination of the feathers on the side of the mandible. It measnvcs an 

 inch and a quarter in length; it is exceedingly slender throughout its whole length, 

 and tapers to a very fine and acute apex, which is not bifid. It is soft and fleshy only 

 for a third of its length, the remainder being quite corneous. Its dorsum has a pretty 

 well-marked longitudinal sulcus. It Terminates posteriorly in an elevated, bifid, papil- 

 lated extremity, the ends of the eornua being free and projecting. Th'> rima glottidis 

 begins about a third of an inch from the end of the tongue, and is two-tenths of an 

 inch long. It has no papillie along its edges, but its termination is papillate, and a 

 row of papiUse extend transversely on either side. Near the angle of the mouth the 

 mucous membrane is thrown up iuto irregular folds, the beginning of the reguhu- 

 longitudinal cesophageal ones. The disposition of the muscular layers of the floor of 

 the month presents nothing peculiar-. 



The a?sophagus measures about four inches in total length, including the proven- 

 Triculus. It is of preTTy uniform diameter throughout, but enlarges a little toward its 

 teru;inaiion : but the proventriculus is the direct continuation of it, and is not sud- 

 denly nor notably largt-r tliau the gullet itself. It is, as usnal, capable of great dis- 

 tension. When undistended, the mucous membrane is thrown up into numerous longi- 

 tudinal folds, quite straight except just at the commencement of the tube, where they 

 are somewhat waved. The eunal has evidently great contractile power, from the 

 thickness of the two layers of muscidar fibres which inclose it. 



The belt of proventrieular glands is about a third of an inch broad. They form an 

 uninterruiited zone quite around the circumference of the can.il, the margin of the 

 girdle being straight and well defined. The color of the mucous membrane is here 

 darker than elsewhere, and has also a dilierence of texture quite appreciable to the 

 naked eye and to the touch. Tne orifices of the solvent glands may be seen as minute 

 punctures, scattered thickly and evenly over the whole surface. 



The gigerinm is very small, not larger in external circumference than tlie proven- 

 tricnlus. It supervenes without any interval, and without any change of direction, 

 diredly upon the proventriculus, with which it communicates by a large orifice. It 



