DE. T. SPElfCEB COBBOLD ON STEONGTLTJS AXEI. 263 



opposite lobe throiigliout its upper two thirds, the lower end 

 bifurcating into subequal divisions. If the ray pattern as a 

 whole be compared with that seen in the ostrich strongyle, the 

 affinity of the two species becomes apparent. The general form 

 and disposition of the rays are similar throughout, the most 

 striking difference being that of the cleavage of the posterior 

 ray, which in Strongylus Douglassii is three-cleft. It is interest- 

 ing to observe that whilst all the rays in the ostrich strongyle 

 are relatively stouter than they are in Strongylus Aocei, they 

 nevertheless individually bear towards each other similar propor- 

 tions in both species *. Thus the thumb- and-finger-like form of 

 the anterior, the paramount antero-lateral, the moderate-sized 

 middle, the isolated poster o-lateral, and the slender posterior 

 rays of S. Axei have their counterpart, ray for ray, in /S'. Doug- 

 lassii. Nevertheless the distinctions already noticed have full 

 speciiic value apart from those affecting other organs. Quite 

 recently another and larger species of Strongyloid worm {Sclero- 

 stoma strutMonis) has been discovered by Dr. Horst in an 

 Ostrich (SfrutJiio molyhdophanes). In Horst's entozoon the ray- 

 pattern is altogether unlike either of the above-named species f- 



The eggs of Strongylus Axei are relatively large, and one can 

 clearly observe the process of yolk-segmentation through the 

 finely-striated integument of the body-wall. The large and con- 

 spicuous spicules are ploughshare-shaped, with a tendency 

 towards division of the shaft, the intercalated small spicule 

 being simple and slightly winged at the centre. This accessory 

 piece can only be seen by strongly pressing the cover-glass, or by 

 dissection. In the ostrich strongyle I did not find a third spi- 

 cule; but I infer that it is present from the general correspon- 

 dence of the larger organs in both species. 



The facts above stated will perhaps be further emphasized by 

 the accompanying approximate measurements : — Head j^-^' to 

 yi^" broad ; tail, above the spicules 2-5-0 "> ^* the narrowest part 

 above the anus of the female -jt-I-^" ; base of the tail-cone i-^^" in 

 breadth, length -g-g-^" ; hood -^-^-fj" in length by -g^" in breadth ; 

 large spicules ^l u" and -jw<s" respectively, accessory piece ^^" 

 in length ; eggs ^\^" to ^is"" i^ length by an average of 4-^" in ' 

 breadth ; distance from the anus to the vulva ■^^' . 



* Journ. Linn, Soc, Zoology, vol. xvi. plate iv. fig. 3. 

 t Notes from the Leyden Museum, vol. vii. p. 263, 



