RANDOM NOTES ON NATURAL HISTORY. 



The Shell - Bearing Mollusca of Rhode 

 Island. 



[BY HORACE F. CARPENTER.] 



Chapter V. 

 Sub-Class. 1. Prosobranchiata. 



Mostly marine mollusks, although a few 

 species inhabit brackish water, some 

 others live in fresh water only, and still 

 others upon the land. The animals are 

 provided with a shell, and generally with 

 an operculum. {All the operculated mol- 

 lusca belong in this sub-class.) They 

 breath by gills or branchife. The sexes 

 are separate in this group, while in the other 

 sub-classes they are united in each individ- 

 ual. 



The Prosobranchiates are divided into 

 four orders, Pectinibranchiata, Scutibran- 

 chiata, Polyplacophora, and Nucleobranchi- 

 ata. 



Order 1. Pectinibranchiata. 



Animal, with pectiniform branchiae ; that 

 is, composed of leaflets arranged like the 

 teeth of a comb, in one or two series or 

 lines, situated upon the upper wall of a 

 respiratory cavity formed by the mantle, 

 having an external opening upon the side 

 of the neck. Shell spiral. 



This order contains fort3'-six families. 

 As these papers are not intended for a com- 

 plete classification of the mollusca, but onl}^ 

 for those inhabiting Rhode Island, it is not 

 necessary to name them all, excepting as 

 they appl}' to the subject in hand. 



Family 1. Muricid^. 



Shell spiral, fusiform ; aperture more or 

 less canaliculate, or simply notched in 

 front ; whorls thickened by varices or nod- 

 ules at each rest period of growth. Oper- 

 culum with subapical or lateral and marginal 

 nucleus. This family is divided into two 

 sub-families. 



1. Muricinae. Three or more varices 

 on each whorl, the varices being nodulous, 

 foliated, or spinose ; canal long or short, 

 but well marked. Operculum ovate. 



2. Purpurinae. Without varices, but 

 tuberculate ; columella flattened ; canal very 

 short, or often a mere notch. Operculum, 

 oblong. 



Sub-Family Muricin^. 



Muricina? contains five genera ; Murex 

 (divided into eight sub-genera) , Urosalpinx, 

 Eupleura, Typhis, and Trophon. Two of 

 these genera, Urosalpinx and Eupleura, are 

 represented in Rhode Island. 



Genus Urosalpinx, Stimpson. 1865. 

 Syns : 



Adamsia, Dunker. Agnewia, T. Woods. 



Fusiform ; no proper varices, which are 

 replaced by longitudinal ribs. 



Distribution. Twenty species, one of 

 which inhabits Rhode Island. 



2. Urosalpinx cinera, Say. 1821. 

 Syns : 



Fusus cinereus, Say. DeKay. Philippi. 



Buccinum plicosum, Gould. Menke. 1830. 



Buccinum cinereum, W. G. Binney. 1870. 



Rapana cinera, Stimpson. 



Urosalpinx cinera, Stm. Dall. Try on, etc. 



Shell elongated-oval, tapering at both 

 ends, coarse, solid, of a reddish brown 

 color, covered with an ash}- gra}- epidermis ; 

 whorls five, crossed by ten to twelve robust 

 costse, and reticulated by numerous fili- 

 form, revolving lines, crenating the edge of 

 the outer lip, which is sharp ; aperture ovate, 

 colored within from light flesh color to dark 

 salmon, sometimes chocolate or purple ; 

 inner lip arched and enameled ; beak 

 short ancl slightly curved ; shell operculate 

 and slightly umbilicate. Length, one inch ; 

 breadth three-fifths. These shells inhabit 

 the Atlantic coasts of the United States, 

 from Maine to Florida. They are second 

 only in abundance to Ilyanassa obsoleta in 

 Rhode Island, and are found in our bay 

 everywhere below Fox Point, on rocks be- 

 tween tides. 



The females lay their eggs in June in 

 small transparent membranous parchment- 

 like vases, attached to the under side of 

 some overhanging rock, just above low 

 water mark. The vases are attached in 

 rows, covering an area of three or four 

 square inches. Each female deposits from 

 ten to more than one hundred of these vases, 

 the process of laying occupying several 

 weeks. 



Genus Eupleura, H. and A. Adams. 



Ranelliform, with a pair of lateral vari- 

 ces, one on each side, with intermediate 

 smaller varices ; aperture dentate within. 



