SPIROTRICHA, HETEROTRICHA 649 



ppsterior end truncated obliquely to left; no peristomal projection; 

 one macronucleus and one micro nucleus; at anterior end, there is a 

 sac connected with the karyophore, which is said to be a "macro- 

 nuclear reservoir"; endocommensals in the colon of Panesthia 

 javanica and P. spadica. 2 species. 



P. hrevis K. (Fig. 305, c-e). Conical in shape; 16-38 (38)m by 9-21 

 (19)m; macronucleus spherical to elongate ellipsoid; micronucleus 

 comparatively large, retains nuclear stains longer than macronu- 

 cleus; anterior sac may sometimes be absent; cysts, 14-19^ long; 

 ovoid; with a spherical macronucleus and a micronucleus; in the co- 

 lon of Panesthia javanica and P. spadica. 



Family 8 Peritromidae Stein 



Genus Peritromus Stein. Ovoid; ventral surface flattened, dorsal 

 surface with hump of irregular outline bearing a few stiff cilia; 

 ciliary rows only on ventral surface; a small undulating membrane 

 at posterior end of peristome; short marginal spines; 2 macro- and 2 

 micro-nuclei; salt water. 



P. calif amicus Kirby (Fig. 306, h). Peristome short; left margin 

 slightly concave; dorsal hump with wart-like protuberances, bear- 

 ing spines (about 12/x long); 16-19 or more ventral ciliary rows; 2 

 spherical macronuclei, one anterior right and the other posterior 

 left of hump; micronuclei 4 (2-5); 89-165ju by 60-96^; salt marsh 

 pools with salinity "1.2-6 per cent" in California. 



P. emmae S. 90-100/x long; creeping on bottom; Woods Hole. 



Family 9 Licnophoridae Stevens 



Genus Licnophora Claparede. Discoid; body roughly divisible 

 into basal disc, neck and oral disc; basal disc for attachment, with 

 several concentric ciliary coronas; neck flattened, contractile nar- 

 rowed part with or without a ventral furrow^ and fibril-bundles 

 (both running from oral groove to basal disc) ; oral disc highly flat- 

 tened, round or ovoid; edge with membranelle zone which extends 

 to pharyngeal funnel; macronucleus long chain-form; without con- 

 tractile vacuole; free-swimming or commensal in fresh or salt water 

 animals. 



L. macfarlandi Stevens (Fig. 306, i). Average 90-1 lO/x by 45-60^; 

 diameter of basal disc 40-45^; basal disc circular; macronuclei in 

 25-35 parts in 4 groups; commensal in the respiratory tree of Sticho- 

 pus californicus. Balamuth (1941, 1942) made excellent studies on 

 its morphology, fission and regeneration. 



