Introduction to Animal Morphology. 179 



encysted therein ; its perfect forms are found in Orthopterous 

 or Neuropterous insects, which it again leaves for repro- 

 duction, and becomes free, losing its mouth and intestine. 

 2. Menu id a; thread-like ; oesophagus short; head papillary; 

 tail undivided papillary in the male, with a double penis 

 (spiculum, spermategse of Dieting) ; egg-shells often with 

 brush-like tassels ; eggs not in chains as in Gordius ; uterus 

 two-horned ; larvce with single cephalic spines, found in 

 idoptera, &c. 3. Sphaeralaridae in the body cavity of 

 Bombus ; with no mouth nor oesophagus (or a mouth opening 

 into the body cavity ?) ; skin with vesicles ; male small, 

 ' ,,u of the size of the female, to which it is organically 

 nod ; female with a simply tubular ovary, a terminal 

 genital opening, and two rows of large cells in the body 

 iv. 



Order 2. Nematoda (Rudolplii) free or parasitic 

 round worms, with a smooth, never ciliated, some- 

 times double refracting cuticle ; rarely with bristles 

 or lateral wing-like expansions beside the head (these 

 are sometimes inconstant, as in Ascaris dactyluris). 

 This layer is chitinoid, and sometimes makes the body 



:, but is less resisting to re-agents than the chitin of 

 Arthropods; it is traversed by fine pores, often annu- 



(1, transversely striped, or laminated, the superficial 

 lay ITS being the most chitinous. The dermis is 

 thinner, obliquely striated, made of granular proto- 



-m, and longitudinal and vertical connective fibres ; 

 it is often traversed by lamina?, and sometimes con- 

 tains unicellular i^lamK \\\ Trichocephalus, there is 



ntral row of rod-like bodies in tli- drrmis. In 

 ventral and dorsal row; in others, 

 nail-like rods. Younir ni-matd<'s usually moult sr \cral 

 tim- lar lamina, thick. - r than tin* inte- 



gument, as it is in most \Vrmes, consists of two 



