2o6 Introduction to A7iimal Morphology. 



They are monoecious, myriapod-like, and live in damp 

 earth. P. juliformis, &c., inhabit the Antilles. P. 

 Cayennensis and Chilensis, South America, others 

 are found at the Cape of Good Hope. Elilers refers 

 these to Arthropoda, Van Beneden to Cotylidae. 

 Schneider places them beside Hirudinea. 



CHAPTER XXX. 



PROVINCE 2. — DEUTEROSTOMATA. 



This province includes two sub-provinces, differing 

 according to the method of the formation of the 

 coeloma. The first of these, Enterocoela, includes 

 those in which the body cavity is formed as an out- 

 growth from the digestive sac, and includes two 

 classes. 



Class 9. Ch^tognatha [Leuckart) — free, marine, 

 monoecious, cylindrical forms, |"- 1" in length, divided 

 into a head, body and tail ; the last is margined by a 

 striated fin.* an expansion of the cellular cuticle, and 

 one or two pair of similar fins may lie farther forward. 

 The surface is often bristled, and in Sagitta draco a 

 lateral bundle of these acts as a fin. The muscular 

 fibres are striped, in four longitudinal bundles, sepa- 

 rated by dorsal-ventral and lateral lines. The head 

 has 4-6 sets of pre-oral setse, and on each side of the 

 slit-like ventral mouth a lateral set of prehensile 

 hook-like bristles. 



* The fins seem to be bristles united by a cuticle. The bristles are 

 brittle, arising in follicles. 



