138 
MOLLUSCA. 
apparently in other Ctenobranchia, the two lobes of the velum, 
the foot, and the cephalic vesicle make their appearance simul- 
taneously. No other provisional organs are present in Trochus ; 
and one of the varieties leaves the egg in a much more imperfect 
stage than the other. Z. wiss. Zool. xxii. p. 288, and pp. 445- 
452, pi. 37. figs. 1-10. 
Jousseauine defines the genera Tinostoma, Cyclostrema, and Skenea in the 
following manner, including Pseudorotella (Sow.) within the first, Adeorhis 
(Wood) within the second, and Spiva (Brown) within the last. R. Z. (2) 
XX hi. pp. 831-335. 
Tinostoma. Pillar-lip thickened, callous, more or less covering the um- 
bilicus. 
Cyclostrema. Umbilicus widely open j whorls more or less embracing one 
another, angular, the upper edge of the aperture projecting much in advance 
of the lower [aperture very oblique]. 
Skenea. Umbilicus widely open; whorls round, scarcely touching each 
other, or even disjoined near the aperture ; peristome circular, the upper 
edge not much projecting [aperture nearly perpendicular. This genus is cer- 
tainly near ii/ssea]. 
Tinostoma morelieri, Martinique, and punctatumy Prince’s Island, W. Africa, 
spp. nn., Jousseauine, 1. c. pp. 335 & 337, pi. 18. figs. 4 & 5. 
Cyclostrema dupUcatum, sp. n., Lischke, Mai. Blatt. xix. p, 10] , Bay of 
Yeddo. 
Cyclostrema lacteum^ locality unknown, viryinice^ ? Madagascar, tncerchUf 
Pulo Pinang, alveolatum^ locality unknown, calameli and militare, Prince’s 
Island, W. Africa, spp. nn. : Jousseaume, 1. c. pp. 388-394, pi. 19. figs. 1-6. 
Circtdus (Jeffr. ?), generic name for Valvata striata (Philippi) and Del- 
phirnda e.vilissima (Philippi), allied to Cyclostrema, not defined. Monterosato, 
Conch. Modit. p. 31. 
Scparutista qmdricarinata and stellaris, spp. nn., the first from Paumotu 
I., the latter from Samoa and Viti I. Garrett, P. Z. S, 1872, pp. 878 
& 879. 
Trochiscus norrisi (Sow.), dentition : Dali, Am. J. Conch, vii. pi. 13. fig. 6. 
[E^lchelus'] Trochus paupei-culus, sp. n., Lischke, Mai. Blatt. xix. p. 105, 
Bay of Yeddo. 
Chlorostoma hrunneum (Phil.), var. n. Jluctuatum, Dali, Am. J. Conch, vii. 
p. 130, Monterey. 
Calliostoma affine, Simoda, palmeri, Guaymas, and yloriostim, Monterey, 
spp. nn., id. 1. c. pp. 125 & 127 ; the two former figured, pi. 15. figs. 14 & 15. 
C. costaium and canaliculatum ( Marty n). On their variations and geogra- 
phical range in California, cf. id. ibid. p. 126. 
[^Zizypkinus~\ Trochus argenteonitens and consors, spp. nn., Lischke, Mai. 
Blatt. xix. p. 104, Bay of Yeddo. 
Thalotia woodsiana, sp. n., Angas, P. Z. S. 1872, p. 611, pi. 42. figs. 4 & 5, 
Portland Bay, Australia. 
Leptothyra ( Carpenter, MS. ) = (Carpenter & A. A dams, neo Swain- 
son, nec Gray, 1836) = (Carpenter, 1804). Type L. sanguinea 
(Carp.). L. paucicostata, sp. n., Dali, 1. c. p. 131, Monterey. [American con- 
chologists persist in wrongly identifying their Californian shell with a thin 
