364 



HOPLOLAIMUS 



M3S- 



reglb. 



kblblG) 



, 

 WMoii Wsubnmh x500 



Fid. 2. An oblique 

 dcrso-ventral view of 

 head of H. coronatus n. 

 sp. The quadrangular 

 nature of the cap is 

 shown in the front view, 

 above. 



constriction so that it constitutes a sort of cap on the 

 front of the head. This somewhat quadrate cap is longitudi- 

 nally faintly six-lobed and each lobe is again longitudinally 

 as well as transversely subdivided. See Fig. 2. The lip 

 region of the male is like that of the female except that 

 it is more nearly hemispheroid, that is, relatively higher 

 and slightly larger. There is a rather robust six-ribbed, 

 yellowish, dome-like structure as the framework of the lip- 

 region, through it is obscured by the nature of the cuticular 

 covering. This framework extends a little back of the 

 labial constriction and its yellow color becomes more evi- 

 dent here. See Fig. 3. Needless to say, therefore, the 

 amalgamated lips are fixed, and shut closely around the 

 anterior extremity of the onchium. Whether the lip region 

 is innervated remains unknown, but no innervations have 

 been seen. The tylenchoid pharynx is of a very robust na- 

 ture and reminiscent of that of Nemonchus. The base of 

 the onchium, or spear, thirteen microns wide by ten high, is 

 very distinctly three bulbed and is about one-fifth as wide as 

 the corresponding portion of the head. Each of the three 

 bulbs is anteriorly somewhat li lobed," presenting sometimes 

 two and sometimes three rather distinct forward pointing 

 knobs. Owing to its index of refraction this lobed base of 

 the onchium, as well as the "hilt," are almost totally invisible in balsam mounts; 

 while the acute tapering anterior part remains distinctly visible, another 

 evidence of the two-fold character (and origin) of the tylenchoid onchium. 

 The posterior attachment of the musculature comprising the ellipsoidal 

 pharyngeal bulb, which is one-half as wide as the head, is not only to the front 

 portion of the bulbs of the onchium but also to their posterior surfaces. The 

 hilt is about half as wide as the bulbous base; the anterior end of the spear is 

 blunt, and the lumen relatively unusually narrow; all which makes the spear 

 an unusually substantial structure, capable of puncturing tissues offering con- 

 siderable resistance. In harmony with this, the ellipsoidal to'obpyriform 

 spear guide is of strong construction, consisting in part of six outwardly bowed 

 elastic elements surrounding the anterior third of the spear and springing back- 

 ward from the base of the cutinized lip region. (Figs. 2 and 3.) This six-fold 

 spear guide has a variable length and width, its form changing with the atti- 

 tude of the spear; when at rest, with a length of fourteen microns, its width 

 is about eight microns, that is, it is about one-third as wide as the correspond- 

 ing portion of the head. In addition to this spear guide the cutinized lip- 

 region fits closely around the anterior portion of the spear for a considerable 

 distance. Both the spear and the spear guide appear to present traces 

 of transverse striation corresponding in fineness with the minute subdivisions 

 of the annules sometimes visible in the subcuticle. The two parts of the 

 spear are rather distinctly set off from each other by a very fine transverse 

 junction mark, as in many Tylenchi. No amphids, deirids or phasmids have 

 been seen. There are no eyespots. The oesophagus is tylenchoid, presenting 

 however, as already indicated, a rather distinct pharyngeal bulb, something 

 rather uncommon in the Tylenchidae. The spherical or oblate median oeso- 

 phageal bulb is half as wide as the corresponding portion of the neck, and is set 

 off both fore and aft from the remaining narrow portions of the oesophagus, 

 very abruptly behind and rather abruptly in front. Behind the median bulb 

 the narrow oesophagus gradually enlarges to form a rather obscure posterior 



