CONCHOLOGY. 



101 



MuHi- 

 valvei. 



DIVISION II. TOOTHLESS. 



Toothless The shells included in this division are not furnished 



Shells. with teeth at the joints. The valves are either simply 



united, or are furnished with a connecting ligament. 

 This division will admit of distribution into three Sec- 

 tions. 



Opercula- 

 ted. 



L. 



Balanus. 



SECT. I. OPERCULATED. 



This Section includes shells which are somewhat co- 

 nical, and have their opening protected by a -testaceous 

 lid or operculum, composed of four plates. 



Genus L. Balanus. 



Shell conical, fixed by its base, and composed of six ar- 

 ticulated valves; the opening closed by an operculumjbrm- 

 ed of four valves. 



Communis, 1. Communis. Shell strong, rugged, with unequal 

 compartments longitudinally costated ; valves of the lid 

 pointed, transversely striated, with a longitudinal groove 

 on the two longest ; diameter at the base sometimes an 

 inch, height nearly three quarters. 

 Brit. Zool. tab. 37, fig. 4. 6. 

 Brit. Shells, tab. 30, fig. 1. 

 Common on the British shores, adhering to rocks, 

 stones, and old shells. 

 Balanoidcs, 2. Balanoides. Shell with six compartments, divided 

 by a deep longitudinal furrow ; mouth large ; lid ob- 

 tuse ; the upper valves slightly striated transversely, 

 the others smooth ; diameter about a quarter of an inch. 

 Brit. Shells, tab. 36, fig. 2, 3. 

 Common on shells and rocks. 

 Piinctatus ^' P uncta f ,ls - Shell with indistinct compartments 

 frequently punctured over ; lid of four valves, with a 

 few striae, the edges of the superior and inferior valves 

 closely united at the top, and indented ; diameter about 

 a quarter of an inch. 



Test. Brit. tab. 1 . fig. 5. 

 Common on rocks and stones. 

 Rugosus, Rugosus. Shell cylindric, usually divided into six 



compartments, which become broad towards the top ; 

 mouth large ; inside margin ridged transversely ; lid 

 composed of four rough angulated pointed valves, not 

 striated ; diameter about three quarters of an inch. 

 Lin. Trans, vol. viii. tab. 1, fig. 5. 

 Not unfrequent on the British shores. 

 CI.iTatut, 5. ClavatuSt Shell long, clavated, slender at the 



base, dilated at the top, and usually cloven into six di- 

 visions ; compartments six, three wide, and three nar- 

 row, wrinkled longitudinally, and faintly striated trans- 

 versely ; length two inches, diameter at the base three- 

 eighths of an inch. 



Ellis's Zoophytes, tab. 15, fig. 7, 8. 

 Found at Weymouth, Dr Pulteney. 

 Tintinna- 6. Tintinnabulum. Shell strong, divided into six 

 bulum, raised and six depressed compartments ; the former run- 

 ning to a point upwards, and striated longitudinally ; 

 the latter contacting to a point downwards, and trans- 

 versely striated ; mouth nearly as large as the base ; 

 length an inch and a half. 



Brit. Shells, tab. 148. 

 Pult. Dorset, tab. 1, fig. 5. 

 This species was first given by Da Costa, but is pro- 

 bably a native of warmer climates, being brought to us 

 on the bottoms of ships. 

 <'o(tatu», 7, Costatus. Shell somewhat conic, ribs equidistant, 



and diverging from the aperture ; operculum sharp Mut-L 

 pointed. ' valves. 



Brit. Shells, tab. 30. fig. 2. s — 'V- 



Discovered by Mr Adams on the coast of Pembroke, 

 and first described by Mr Donovan. 



8. Conoides. Shell conic, valves smooth, pointed at Couoides, 

 the apex ; aperture very small. 



Brit. Shells, tab. 30, fig. 3. 

 Found by Mr Bryer of Weymouth, and first descri- 

 bed by Mr Montagu. 



9. Striatus. Shell compressed; compartments strong- Striitus, 

 ly ribbed in an oblique direction to each other, and 



finely striated across the ribs ; margin of the base irre- 

 gularly serrated ; aperture oblique, closed by a lid, and 

 so obscured, that it is scarcely discernible ; diameter a 

 quarter of an inch. 



Brit. Zool. tab. 38, fig. 7- 



Brit. Shells, tab. 36, fig. 1. 

 Common on the British shores, adhering to shells 

 and to the roots of alga?. 



10. Spongeosus. Shell ovate, with six angulated Sponger 

 wrinkled compartments, terminating in much elevated 3us i 

 points, and furnished with numerous spines ; base con- 

 centrically wrinkled, beneath which is a cup rounded 



at the bottom, whose margin corresponds with the cir- 

 cumference of the base ; lid of four valves, the posteri- 

 or pair long and hooked forward, the anterior pair 

 rough, with decussated striae; length about half an 

 inch. 



Test. Brit. tab. 17- fig. 4, 5, 6. 



Found by Mr Bryer of Weymouth imbedded in a 

 particular species of sponge resembling Spongia tubu- 

 losa. 



In a piece of the same species of sponge from the 

 coast of Devon, Mr Montagu found another species al- 

 lied to the preceding. It was mutilated, but enough 

 remained to point out some of its peculiar characters. 

 The cup or base was in the form of an inverted cone, 

 perforated at the smaller end, thick, margin of the cup 

 bevelled off to an edge, which is striated ; inside fur- 

 nished with annular ridges, and lined with a mem- 

 brane ; outside rough, with tubercles and broad pro- 

 jecting plates. 



In our opinion, the Balanus spongeosus ought to form 

 a new genus, as it differs in character and economy 

 from all the other species of the genus Balanus. 



Genus LI. Coronula. 



Shell regular, sub-rotund, sub-conical, divided into hvelve 

 area, with an opening both in the inferior and superior 

 part; superior opening closed by a four-valued lid. 



Obs. The shells of this genus, together with their 

 inhabitants, are found imbedded in the fat of the whale, 

 so as to leave only the superior aperture uncovered. 



1. Diadema. Shell with six depressed, flat, trans- rjj a d e ma> 

 versely striated compartments, and six prominent ones, 

 with elevated longitudinal ridges open at top ; cavity 

 funnel shaped, hexagonal ; height an inch, diameter at 

 the base about three inches. 



Brit. Shells, tab. 56. fig. 1 . % Lepas Diadema. 



Found in whales, which occasionally visit the British 

 shores. 



SECT. II. PEDUNCULATED. 



The shells of this Section are furnished at their base 

 with a cartilaginous flexible tube, by which they are 

 immoveably fixed. These tubes are capable of being 



