MOLLUSCA, 
683 
12, Port Dalhousie, delta of the Irawady, on mud between tidemarks [probably 
=Ass. miniata of the Recorder, Ann. & Mag. Nat. Hist. 1866, xvii. p. 204.] — 
The same species, Assiminea rotunda, sp. n. ( Fairbank), cornea, euhconica, 
marginata, spp. nn., are described and figured by Blanford, Ann. & Mag. Nat, 
Hist. June 1867, xix. pp. 381-386, India. The genus Optediceros is identical 
with Assiminea. 
Helicinid^. 
Helicina. The dissection of several specimens of Helicina 
titanica (Poey) by C. Isenkrahe proves that this genus agrees, 
with regard to the radula, the presence of a peculiar organ ad- 
hering to the stomach, and the position of the nervous gan- 
glions, more with Neritina than with Cyclostoma. Therefore 
the author is inclined to remove the Helicinacea from the other 
operculated Pulmonata, uniting them with the Trochidcs and 
NeritidcB under TroschePs name Rhipidoglossa. The separation 
of the sexes and the absorption of the inner septa between the 
wliorls is confirmed by the author^s investigations. Isenkrahe, 
Helicinao titanica: Anatomc; or in TroschePs Arch. f. Natur- 
gcschichte, xxxiii. pp. 50-72, pi. 1. 
Helicina zelehori, sp. n., Pfeiffer, and H. dtinheri, sp. n., Zelebor, Verhandl, 
zool.-bot. Gesellsch. Wien, xvii. pp. 807, 808, Nicobar Islands. 
Helicina (Gray) (Pfr.), Martens, 1. c. p. 166, pi. 4. fig. 20, 
Java?, Celebes, Timor, and Amboina; H (Martens), fig. 17, Timor j 
H. suturalis (Martens), fig. 18, Amboina, Ceram, and Burn ; H, albocincta 
(Hombron & Jac(lumot ?), 1. c, fig. 21, Banda Islands ; H. biconica, sp. n*, 
Mousson in collectione, Martens, Ic. p. 169, Java; H. idee (Pfr.)=zo«e (Pfr-)# 
I. c. pi. 4. fig. 19, Amboina ; H. borneensis (Martens), I c. p. 171, Borneo ; 
H.parva (Sow.) (Martens), 1. c. fig. 22,‘Batjan and Halmahera. 
Helicina discoidea, sp.n., oceanica, sp. n., and maugerice (Gray), var. rubi^ 
cunda. Pease, Am. Journ. Conch, iii. pp. 226, 227, Taliaa, Kingsmill, and 
Raiatea islands, Polynesia. — II. jlavcsccns and zigzag, spp. nn.. Pease, ibid, 
pp. 228, 229, pi. 15. figs. 25 and 26, Mangaia and Oualoii islands. 
Helicina rawsoni and bryanti, spp. nn., Pfeiffer, Journ. Conch, xiv. p. 165, 
Inagua, Bahama Islands. 
Helicina (subgen. Oligyrd) orbicidata , hanleyana (Pfr.), cTirysocheila 
(Binney), and subglobulosa (Poey) are briefly described and figured, and the 
head of the living animal and the lingual dentition of the first and another, 
undetermined species figured by Binney, Land- and Freshwater Shells o£N. 
Am. iii. pp. 107-112 and 116. ' ' ' 
Helicina {Perennd) lamellosa. Guppy, Ann. & Mag. Nat. Hist. xix. p. 260, 
pi. 10. fig. 4, and Proceed. Scientif. Assoc. Trinidad, ii. p. 136, Cotoras Islets, 
Trinidad. The subgenus Perenna is new, and distinguished by the concentric 
striee of the operculum and the spiral ridges of the shell. H. lirata (Pfr.) is 
included in it. 
SOLENOCONCHA]). 
Pentalium octogomim (Lam.), Hakodate. Schrenck, 1. c. p. 381. 
Siphonodenfalium lofotense, affine, subfusifonne, and pentagonum, spp. nn.> 
Sars, from the Lofoten Islands, the last two also in the Bay of Christianiai 
The living animals are described, and some particulars concerning their ana- 
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