33S On the genua Pompholyx and Us Allies, 



* 



The odontophore i> about lour times as long a> ir is wide. 



It is broadly reflexed at its anterior extremity, and the sur- 

 face is moderately convex. 



The teeth arc transverse in a line almost straight. The for- 

 mula is 22 — 1 — 2l\ or forty-live teeth in a row, and there are 

 about one hundred and fifty rows. 



The central tooth is nearly twice as long as it is broad. The 

 cusp La half as long as the hast-, and bifid or furnished with two 

 minute pointed teeth at the posterior extremity, and occasion- 

 ally two prominent tubercles on, the base. The inner laterals 

 are much wider than the central tooth, and thecusps are nearly 

 twice as long as the bases. They are rounded-rhomboidal 

 and slightly indented, having a trilobate appearance. 



The decrease in width and the lobed appearance become 

 more evident toward the margin of the odontophore. The cusps 

 of the outer live rows are \<cx\ much compressed, and hence 

 have a tridentate rather than a trilobed appearance. 



While the teeth appear to be of a purely chitinoua consis- 

 tency, and are quite insoluble in caustic potash, the buccal 

 plate is liable to destruction from continued boiling in a con- 

 centrated solution. 



Circulatory system. The heart is small and occupies a posi- 

 tion midway between the buccal mass and the stomach, and 

 laterally is between the oesophagus and the descending intes- 

 tine. One principal hi l-vessel .-applies the liver and adja- 

 cent viscera, and another the buccal region, the tentacle-, and 

 the head. A -mall branch accompanies the o\arian duct and 



•rapanying gland-, while another supplies the stomach. 

 Reproductivi system,. The ovarian duct, or vagina, opens 



into the pulmonary chamber, close by the ami- and ju-t within 



the mantle margin. A -mall sac, the "genital bladder" of 

 Leidy, is situated near tin- end of the vagina. Behind this, the 

 oviduct i- dilated, forming a fossa corresponding to the uterus. 



Further back a gland opens into the oviduct, beyond which the 

 r i- a_raiu BOmewhal lobed and dilated.' The ovary is 



