MOLLUSCA. 



129 



Genus Rissoa (Page 10.) 



56. Rissoa tristriata. 



Rissoa tristriata, Thompson, Ann. Nat. Hist., V, pi. 2, f. 10; 

 Macgillivray, Moll. Ab., p. 151. 



Shell conical, ovate, thin, glossy, subdiaphanous ; body ven- 

 tricose, somewhat longer than the spire ; spire consisting of 

 four moderately convex volutions, defined by a rather shallow 

 sutural line, which is accompanied by a narrow spiral line, with 

 also two smaller lines and three stria;, terminating in a rather 

 obtuse apex ; aperture large, of a short oval form, and occupy- 

 ing about half the length of the body ; outer lip thin, destitute 

 of any thickening behind ; colour yellowish-white, the body 

 with three bands of squarish red-coloured spots. Length a 

 twelfth of an inch ; diameter two-thirds of its length. 



Found by Mr. Alexander Murry, in shell sand, from the Bay 

 of Cruden. 



57- Rissoa gracilis. 



Rissoa gracilis, Macgillivray, Moll. Ab., p. 152. 



Shell thin, pellucid, glossy, turreted, subcylindrical ; consist- 

 ing of six moderately convex volutions, defined by a deep 

 sutural line; aperture obliquely ovate, a little contracted above, 

 occupying about a fourth of the entire length of the shell; outer 

 lip complete, a little thickened externally ; inner lip narrowly 

 reflected on the columella, with a slight cavity behind ; body 

 ferruginous around the aperture ; spire cream-white. Length 

 somewhat more than the twelfth of an inch ; diameter a fourth 

 of its length. 



In form it resembles Rissoa striata, but is more elongated, 

 and is nearly allied to Rissoa ruber, which, however, is less 

 attenuated with a rounded aperture. 



Found by Miss Anne Macgillivray, in shell sand, on the 

 beach between the estuaries of the Dee and Don, Aberdeen- 

 shire. 



Genus Trochus (Page 18.) 



14. Trochus Martini, pi. LVII, f. 11. 



Trochus Martini, Brown, Wernerian Mem., VIII, p. 51, pi. 

 1, f. 2G. 



Shell conical ; consisting of seven flat-sided volutions, well 

 defined by the suture, and terminating in an acute apex ; the 

 whole covered with five or six tubcrculatcd spiral ridges, which 

 can only be distinctly seen by the aid of a strong lens, the 

 lower ridge of each volution being more prominent than the 

 others ; base imperforate, flat, and a little concave, furnished 

 with numerous tuberculate, concentric ridges ; whole surface 

 citron or flesh-coloured, streaked with nearly equidistant, red- 

 dish-brown, irregularly-shaped spots ; aperture subquadrate, 

 compressed, and nacred within. 



First discovered by Major Martin, of Mayville, Ayrshire ; it 

 has since been dredged by Mr. Smith, of Jordan Hill, in the 

 Kyles of Bute ; by Professor Forbes, off the Isle of Man ; and 

 near Dublin, by Mr. Alder, of Newcastle ; and is said to have 

 been found on the Aberdeenshire coast. 



5. Trochus perforatus, p. 18, pi. LVII, f. 9, 10. 



Genus Tornatella — (Page 21.) 



2. Tornatella pellucida. 



Tornatella pellucida, Macgillivray, Moll. Ab., p. 158. 

 2 K 



Shell ovate, very thin, diaphanous, and glossy, conical, some- 

 what fusiform ; volutions divided by a well defined sutural line, 

 nearly flattened on the sides, and tapering to a sharp apex, 

 and are longitudinally striulated, and spirally striated ; body 

 nearly twice as broad as the length of the spire, more deeply 

 striated at the base and towards the suture, where there are 

 two punctulate impressed lines, the basal stria; minutely crenu- 

 late ; edge of the volutions simply incurved; aperture oblong, 

 narrow, the superior angle being considerably contracted by the 

 convexity of the lower volution of the spire ; outer lip 

 extremely thin; columella with an obscure plait; colour cream- 

 white, with two faint reddish bands on the body. Length 

 somewhat more than an eighth of an inch; diameter more than 

 half its length. 



" It closely resembles a young Tornatella fasciata, but differs 

 in having the spire longer and more pointed, in wanting the 

 channel in the suture formed by the involution of the spiral 

 turns, in having two impressed lines near the posterior margin 

 of the turns, and in being differently coloured. The three 

 reddish bands, however, are analogous to the reddish spaces 

 between the white bands in Tornatella fasciata." 



Found in the Bay of Aberdeen, by Professor Macgillivray. 



3. Tornatella pusilla. 



Tornatella pusilla, Macgillivray, Moll. Ab., p. 158; Voluta 

 fusiformis, Turton, Conch. Diet., p. 259. 



Shell very thin, transparent, glossy, ovate, conical, and sub- 

 fusiform ; spire with three distinctly divided, slightly convex 

 volutions, tapering to an obtuse apex ; body about twice as 

 broad as the length of the spire, with three spiral, punctulate 

 stria;, which are strongest below, obsolete and distant on the 

 upper two-thirds, crowded towards the suture; aperture oblong, 

 narrow, considerably contracted at its upper extremity, by the 

 convexity of the lower volutions ; outer lip extremely thin ; 

 columella with an inconspicuous, oblique, obtuse plait or nodo- 

 sity, terminating the inner lip; colour cream-white. Length 

 one-twelfth of an inch ; breadth half the length. 



" This species has the spire shorter than Tornatella fasciata 

 and Tornatella pellucida. It seems to agree in most respects 

 with Turton's Voluta fusiformis, but differs in being only a 

 third of the size, and spirally striate." 



Genus Jaminia — (Page 21.) 



10. Jaminia scalaris. 



Odostomia scalaris, Macgillivray, Moll. Ab., p. 154. 



Shell thin, transparent, and glossy, ovately conical; consisting 

 of five faintly striated, moderately convex volutions, well defined 

 by a canaliculate suture, towards which the superior margin is 

 suddenly inflexed ; aperture ovate, occupying nearly the whole 

 length of the body ; outer lip thin ; columellar lip somewhat 

 inflexed, and terminating in a prominent plait on the columella: 

 colour cream-white. Length not a twelfth of an inch; breadth 

 half its length. 



Macgillivray says " this species differs from all the others, in 

 having the pillar lip inflexed, in wanting the umbilicus, and in 

 the subscalar form of the spire." 



Found by Professor Macgillivray, in shell sand, between the 

 estuaries of the Dee and the Don, Aberdeenshire. 



11. Jaminia plicatula. 



Odostomia plicatula, Macgillivray, Moll. Ab., p. 156. 



