18 Geary i it a Sweet .- 



two nodules had one male, and the two other nodules each had two 

 males. In the other nodules dissected no male was found at all. 



In structure, the worm very closely resembles 0. gibsoni, to which 

 it has undoubtedly close affinity, and in view of the detailed descrip- 

 tions of that worm already published (and referred to above) it is 

 unnecessary to repeat here a minute general description. I have 

 therefore contented myself with a statement of the specific charac- 

 teristics of the Indian worm, and a careful comparison with other 

 allied forms as indicative of the reasons for the establishment of a 

 new species. Incidentally, light is thrown on one or two points of 

 general interest as regards the specific diagnosis of Nematodes. 



The characteristics of this worm may be summarised as follow? 

 (cf. Tables 1, 2, 3, and Figures 5, 6, 7, 8, 9), the variations being 

 discussed in detail later. 



Onchocerca indica, n. sp. 



Male. — 3.38 to 9.3 cm. long (average 5.69 mm.); diameter of 

 central portion of body, .175 to .220 mm. (average, .198 mm.), 

 tapering to each extremity. Anterior end straight and without in- 

 terruption, posterior end often spirally coiled, having a cloaca! 

 ■swelling on which the cloaca opens, behind which the tip of the 

 tail is generally bent sharply towards the ventral surface, forming 

 a hook. Cuticle, .003 to .004 mm. thick in the central region of the 

 body, where also it has regular rounded transverse ridges, the depres- 

 sions between which are .005 to .006 mm. apart at the maximum, 

 these ridges becoming smaller and less conspicuous as they approach 

 the two ends, where they are absent; finer striae were not detected 

 Mouth terminal with three slightly marked lips and three papillae 

 (not always easily seen) close behind the level of the opening. 

 Oesophagus long, from over .847 to 1.22 mm. (average, over 1.051 

 mm.), thick-walled, .031 to .039 mm. (average. .036 mm.), and 

 generally with a well-defined bulb (or " eardia "), .062 to .069 

 {average, .064) mm. long, and .047 to .060 (average, .053) mm. wide, 

 at the junction of the oesophagus, with the typical thin-walled, 

 straight intestine. Nerve ring surrounds oesophagus usually at 

 .188 mm., though sometimes at .172 mm. (average, .182 mm.) from 

 the anterior end, and where seen the excretory pore appeared to be 

 situated at .219 to .282 (average, .250) mm. from the anterior end 

 Oloacal opening at .062 to .086 (average, .07) mm. in front of the 

 tip of the tail, the diameter of the body at the level of the opening 

 being .042 to .062 (average, .053) mm. Anal papillae somewhat 

 variable, generally eight or nine pairs in number, but sometimes 



