Introduction to Animal Morphology. 155 



PROVINCE i. ARCH^OSTOMATA* (Huxley}. 



CLASS i. TURBELLARIA (EJircubcrg}. Unjointed, 

 rarely parasitic, ciliated, leaf- or ribbon-like worms, 

 rarely with chitinous processes or bristles (not arising- 

 in follicles), or circlets of stronger cilia (Dinophilus). 

 The integument consists of cells or of undivided pro- 

 toplasm, containing, in the aquatic forms, nettle-cells 

 scattered or clustered ; sometimes rod- or spindle-like 

 bodies, with (Meckelia) or without appended threads 

 may exist in capsules, like those of the true nettle- 

 cells (absent in Geoplana, Schul. 



The integument may also contain chlorophyll (Vortex 

 viridis, Convoluta Schultzii) or calcareous concretions (Sidonia 

 . The component plastides are best seen in land 

 planarians, where the glandular elements are divided into 

 superficial and derp. The sub-cutaneous muscular layer 

 consists of usually three lamina?, an outer circular, well marked 

 in Bipalium and Dendrocoelum, often umlifferentiated in 

 others, a middle, longitudinal (the strongest), and an inner 



ular.f The fibres in most are but spindle-cells loosely 

 scattered in a net-work of connective tissue (except in Ne- 

 mertinea). 



Cotylidoe, or united to Chaetopoda to form a group Annelida. Rotatoria 



.ced by many among the Arthropods near Crustacea. Bryozoa and 



Tunicata are usually and naturally united to Brachiopoda to form a sub- 



>n Molluscoida, but as the Mollusca proper are only an extreme of 



lib-division of Venues, it would be still more natural 

 1 them all together in the one sub-kingdom. ] IOWCYIT. as for con- 



.:rly, it is to a large extent 



arbi': : demarcation is drawn ; so, though many eminent 



letain the Tunieates, &c., with the 

 nfi.inr in my classification. 

 . .};), be in;,' prim. try embryi >nic OIH-S, .sin ml! 

 'hcsub-kiii. .at in the ptvM-nt condition 



apply them to all the included I 

 f Amor;/ nt. 



