Introduction to ^iiii/mil j\Ior^hology. 109 



Cestidse, including the Venus' girdle (Cestum), with a long 

 stomach, and Vexillum with a larger funnel. 



4. Lobat£e {Eschscholiz) — body with a pair of antero- 

 posterior lobate processes ; ridges and ctenophoral canals of 

 unequal length. The families are : Eurhamphoeidas — with 

 beak-like apical, lobate, oral pole and no tentacles ; Bolinidae — 

 with rounded apical pole, small tentacles not in sacs, and 

 with the four shorter radial ridges in pairs, smooth on the 

 surface (Bolina), or papillose (Bolinopsis) ; Mnemiidae — with 

 oral lobes separated from the lateral parts of the body by 

 grooves, and two of the radial canals ending in arabesque con- 

 volutions in the oral lobes. Eucharis and Chiajea are papillose, 

 the others are smooth, with large (Mnemiopsis), or small 

 auricles (INInemia, Lesueuria) ; Calymmidse — with lobate pro- 

 cesses arising from the apical end, overlapping the oral end 

 as a mantle ; Ocyroidae — with forked lobes prolonged from 

 the apical end. 



The aberrant Sicyosoma {Gegefibaur), with no ctenophores 

 nor gastrovascular canals, but with nettle cells in the body 

 wall, may form a fifth order, or may be the young of Cestum 

 (^Agassiz), or an Actinian larva (A'/'ti/z// and Leuckarl). 



CHAPTER XVIII. 



Class 2. Actinozoa. 



Radiated coelenterates with tentacles (Fig. 17, /) 

 round the mouth at the distal pole, and with a 

 stomach cavity separate from, suspended within, 

 and opening" into, the body cavity [s], the portion of 

 which around the stomach (perivisceral space) is di- 

 vided into compartments by vertical, radiating, mem- 

 branous partitions, mesenteries (Fig. 1 7, ;;/), in which 

 the sex-organs are developed. Thus in transverse 



