150 UNITED STATES NATIONAL MUSEUM BULLETIN 29 6 



15a. Opercular teeth becoming progressively larger toward dorsal or attachment 



end C. heterodontus 



15b. Opercular teeth of various size, but variously distributed on low hillocks 



C. minutus 

 16a. Apex of operculum with well-developed spine or hook on each side . . 17 



16b. Apex of operculum without such strong spines or hooks IS 



17a. Apex with straight spine, with 12 or more long hyaline spines of approxi- 

 mately equal length along operculum W. aapta 



17b. Apex with curved hooks, a pair of weak irregular lateral bars present 



Weltneria spinosa 



18a. Operculum with many small spines and hairs W. hirsuta 



18b. Operculum ornamented with many small bifid and crenulated teeth, a 



reticulated pattern medially and rows of fine dots laterally . W, reticulata 



19a. Operculum studded over outer surfaces with numerous blunt, heavy, nodular 



teeth, margins with over 30 simple teeth Berndtia nodosa 



19b. Operculum superficially smooth, except for many small marginal teeth . 20 



20a. Marginal teeth simple B. purpurea 



20b. Marginal teeth serrated into 3-5 points arranged in an arc . . B. fossata 

 21a. With a pair of strong spines or hooks at the apical end of the operculum . 22 



21b. Without such paired apical spines or hooks 25 



22a. Apical projections are hooked, or with strong spur-like teeth on spine to 



make it appear hooked 23 



22b. Apical projections not hooked 24 



23a. Projection itself is uniformly and strongly hooked . Lithoglyptes spinatus 



23b. Spur-like tooth on projection may give hooked appearance 27 



24a. Projections long, bristle-bearing 2 pairs of processes or operculum ... 26 

 24b. Projections shorter, with bifid teeth and few short hairs . . . . L. mitis 



25a. Hooks or spines present, not paired apically L. scamborachis 



25b. No hooks or spines present L. indicus 



26a. Both pairs of processes conical, erect L. bicornis 



26b. Pair toward attachment end strongly hooked L. ampulla 



27a. Spur-like tooth common, most prominent teeth on operculum, large, simple, 



strong lateral bar L. habei 



27b. Spine rarely spurred, most prominent teeth on operculum bifid, lateral 



bar absent L. wilsoni 



28a. With paired anterior opercular processes 29 



28b. Operculum merely pointed anteriorly 30 



29a. One posterior hook on operculum Kochlorine hamata 



29b. No posterior hooks, opercular margin with large anchor-shaped teeth 



K. anchorella 



30a. With two posterior hooks on operculum K. bihamata 



30b. With no posterior hooks on operculum 31 



31a. Lateral bar and retractor pallii rostralis present K. floridana 



31b. Lateral bar and retractor pallii rostralis absent 



Kochlorinopsis discoporellae 

 32a. Ovarian disk tending to extend posteriorly rather than to either side . . 33 

 32b. Ovarian disk extending to right side of slit in shell . . Trypetesa lateralis 



33a. Attachment area oval, not twisted 34 



33b. Attachment area elongated, twisted spirally T. nassarioides 



34a. With well-developed comb collar inside mantle aperture . . . T. lampas 

 34b. Without comb collar T. habei 



