110 MR. W. K. PARKER ON THE STRUCTURE 



Part of the bialate septal base (tr) and part of the nasal labyrinth of one side is here 

 shown. We here see that the trabeculse have only partially lost their flatness, and form 

 a partial subnasal floor, and that the alinasal wall (nw), after giving off the " alinasal " 

 turbinal (atb), ends externally in a blunt process, and internally in an incurved bifurcate 

 rod (ial). 



The forks of this rod are continuous with the corresponding vomerine half ; the halves 

 of the vomer are joined by a long commissure into a flat bone, notched at both ends ; the 

 long posterior ends articulate with the ethmo-palatines, and the shorter anterior forks pass 

 into a cartilage shaped like a breast-plate. This plate, being gently emarginate behind, 

 forms a fenestra with the help of the bony vomer ; it narrows gently forwards, and ends 

 in a pair of straight styles. 



This plate is nothing more or less than a forward continuation of the vomerine 

 cartilages (vc), the unossified parts being bridged over by a commissure. For relative 

 size, these vomerine cartilages * have their rivals only in the Snake, the Rhea, the 

 Hemipod, and in certain low-typed Passerines of the southern world (Notogcea), namely, 

 Anceretes parulus, Pipra auricapilla, and in that remarkable type Pachyrhamphus. 



Other characters in the "Wren's face are of importance, as illustrating what is com- 

 monly found in the numerous related forms. 



The lacrymal (fig. 7, I), often absent, is here very small ; the lateral ethmoid (eth, pe), 

 on the other hand, is very large, and shows itself on the upper view ; its inferior angle is 

 separately ossified as an " os uncinatum " (ou), or palato-trabecular conjugational bone. 



Between and below the eyes the trabecular crested bar (tr) has been freely differentiated 

 from the ethmo-presphenoidal bar (pe), and the long overlapping process of the pterygoid 

 has become segmented into a distinct " mesopterygoid " (ms.pg), soon, however, to 

 ankylose with the palatine. In this rather young bird the transpalatine (fig. 5, tpa) was 

 scarcely confluent with the broad part of the long and slender palatine (pa). The deli- 

 cate pterygoids (fig. 5,p>ff) here are more like the epipterygoid of the Lizard than its ptery- 

 goid ; but the terminal part (apex of the bar) is alone upturned. This upturned part is 

 very long in some " Coracomorphse " — e. g. Coccothraustes, one of the most specialized of 

 the conirostral division of the group. In certain subfamilies of the " Coracomorphse," 

 although the maxillo-palatine processes do not solder the upper jaws together, yet the 

 palate is made more solid by means of an additional bony wedge, the " palato-maxillary ;" 

 this grows in between the prepalatine bar and the body of the maxillary. In the "Car- 

 dinalidse " (Plate XX. fig. 13, pa.mx) it is a large and thick bone ; it is somewhat 

 smaller in the Buntings (Mnberiza, Plectrophanes, Phrygilus), and also somewhat smaller 

 still in the " Icteridse," " Sylvicolidse " (Mniotilta, Denclroeca, Trichas, Chlorophanes), 

 and in the " Tanagridse" (Tanagra, Prionocheilus, Stephanophorus). 



That curious bone, the " os uncinatum," the matrix of which was first developed as a 

 conjugational bud from the trabecula, is very large in the Grosbeak ( Coccothraustes), as 

 in its climbing isomorphs the Parrots. The " posterior conjugational processes," " basi- 

 pterygoids," and their counterparts on the pterygoid bones are early arrested in the 



* If the Wren had possessed a " recurrent alinasal," like the long forked one of Vireosylvia olivacea, the two 

 subsqital floors would have reached each other. 



