2 PEOCEEDIXGS OF THE NATIONAL MUSEUM. vtL. 65. 



ampliicls shifted as in some forms of Paratnermis, one might regard 

 it as being closer to this genus, but the paired spicula and the num- 

 ber (four) of the head papilhie speak against such a rehitionship, 



ALLOMERMIS TRICHOTOPSON, new species. 



Plates 1-2. 



Number of specimens. — 3 females, 2 males. 

 Hahitat. — Soil, Jamaica. 

 Measurements. — Formula of Cobb: 



Pharynx. Xerve-ring. Neck. Vulva. Posterior end of fat body. 



„ , ? ]L9 ? 61.0 98.4 ^„ 



Female: ^ ^^-5 ^ ^— 2 o 12 mm. 



Male sex opening. 



,, , ? 2.5 ? 50 98.0 ^^ 



Male: ^ t-^ s^ j— c r" 5 9. 7 mm. 



Formula of de Man: 



Female Male 



a— 83. 3 66. 6 



^ "^ ? 



T-76. 50. 



Length of female Xo. 2-11 mm. 

 Length of female Xo. 3-16 mm. 

 Length of male Xo. 2-11 mm. 



The size of this species if compared with that of other Mermithids 

 is rather small. The cuticle was detached from the hypodermis and 

 so its thickness could not be exactly measured. On the surface is a 

 layer of cross-fibers. 



The hypodermis has apparently eight longitudinal chords.^ of 

 which the lateral, measured on the surface, are about 42 microns 

 wide, the dorso-medial about 8 microns, the ventro-meclial and the 

 four submedial 3-4 microns; it seemed that all of them are about 

 equally distant from each other. 



The head-end is bluntly rounded as shown in Figures 1-4. Its 

 structure is very characteristic. The mouth opening is situated some 

 distance behind the head papillae and has therefore a decidedly 

 ventral position. I know no other nema with such remarkable loca- 

 tion of the mouth opening. Some species of the genus Paramermis 

 have a shifted mouth opening, but there it still lies between the 

 anterior extremity and the circle formed b}^ the papillae. Only in 

 P. gastrostojna, a species described earlier by the writer, and in P 

 hempeU, described recently by Micoletzky, and closely related tc 

 P. gastrostoma, is the mouth opening situated on the same level witl 

 the head papillae. 



" Proposed by Doctor Colib for use in place of the rather unsatisfactory term " longitu- 

 dinal fields"; it may he ns<'il in the same way as the <!riiiiaii term " Liinn'swiilste." 



